Apparatus, methods, and compositions for endodontic treatments

ABSTRACT

Examples of apparatus, methods, and compositions for endodontic treatments are described. The apparatus can include a fluid platform configured to substantially retain fluid in a tooth chamber during treatment. The fluid platform can help maintain fluid circulation in the tooth chamber as fluid flows into and out of the tooth chamber. The apparatus can also include a pressure wave generator configured to generate acoustic waves that can be used for cleaning root canals and tooth surfaces in the tooth chamber. Examples of pressure wave generators include a liquid jet, an electromagnetic energy delivery device, and an ultrasonic device. The fluid can include antiseptic or antibacterial solutions to assist in tooth cleaning. The fluid may be degassed to have a reduced dissolved gas content (compared to non-degassed fluids used in endodontic treatments), which may improve the effectiveness of the pressure wave generation or the cleaning.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/279,199, filed Oct. 21, 2011, entitled “APPARATUS, METHODS, ANDCOMPOSITIONS FOR ENDODONTIC TREATMENTS,” which claims the benefit ofU.S. Provisional Patent Application No. 61/405,616, filed Oct. 21, 2010,entitled “APPARATUS AND METHODS FOR ROOT CANAL TREATMENTS,” and U.S.Provisional Patent Application No. 61/485,089, filed May 11, 2011,entitled “APPARATUS AND METHODS FOR ROOT CANAL TREATMENTS,” each ofwhich is hereby incorporated by reference herein in its entirety.

BACKGROUND Field

The present disclosure relates generally to dentistry and endodonticsand to apparatus, methods, and compositions for treating a tooth.

Description of Related Art

In conventional root canal procedures, an opening is drilled through thecrown of a diseased tooth, and endodontic files are inserted into theroot canal system to open the canal spaces and remove organic materialtherein. The root canal is then filled with solid matter such as guttapercha or a flowable obturation material, and the tooth is restored.However, this procedure will not remove all organic material from thecanal spaces, which can lead to post-procedure complications such asinfection. In addition, motion of the endodontic file may force organicmaterial through an apical opening into periapical tissues. In somecases, an end of the endodontic file itself may pass through the apicalopening. Such events may result in trauma to the soft tissue near theapical opening and lead to post-procedure complications.

SUMMARY

Various non-limiting aspects of the present disclosure will now beprovided to illustrate features of the disclosed apparatus, methods, andcompositions. Examples of apparatus, methods, and compositions forendodontic treatments are provided.

In one aspect, the apparatus can include a fluid platform configured tosubstantially retain fluid in a tooth chamber during treatment. Thefluid platform can help maintain fluid circulation in the tooth chamberas fluid flows into and out of the tooth chamber. The fluid platform canregulate pressures within a tooth chamber in a tooth. The fluid platformcan include one or move vents that permit fluid to leave the tooth(e.g., to inhibit over-pressurization or under-pressurization of thetooth chamber) and/or can inhibit air from flowing into the toothchamber (which can inhibit generation of pressure waves or acousticcavitation in fluid in the tooth chamber). The fluid platform maypromote fluid circulation in the tooth chamber by retaining fluid (andfluid momentum) in the tooth chamber.

In another aspect, the apparatus can include a pressure wave generatorconfigured to generate acoustic waves that can be used for cleaning rootcanals and tooth surfaces in the tooth chamber. The pressure wavegenerator can include one or more of a liquid jet device, a waveguidethat propagates light energy into a tooth chamber, an ultrasonic device,or a mechanical stirrer.

In another aspect, the fluid can include antiseptic or antibacterialsolutions to assist in tooth cleaning. The fluid may be degassed to havea reduced dissolved gas content (compared to non-degassed fluids used inendodontic treatments), which may improve the effectiveness of thepressure wave generation or the cleaning.

All possible combinations and subcombinations of the aspects andembodiments described in this application are contemplated. For example,one embodiment can include a fluid platform and a pressure wavegenerator. Another embodiment can include a fluid platform with one ormore vents. Some embodiments can include a fluid platform with a fluidinlet for delivering fluid to the tooth chamber and/or a fluid outletfor removing fluid from the tooth chamber. In some such embodiments, thefluid outlet may be vented, which may help regulate pressure in thetooth chamber. Another embodiment can include a fluid platform thatdelivers a degassed fluid to the tooth chamber. Another embodiment caninclude a pressure wave generator comprising a liquid jet device, inwhich the liquid jet comprises a degassed liquid. Other examples ofcombinations of apparatus are described herein.

For purposes of this summary, certain aspects, advantages, and novelfeatures of certain disclosed inventions are summarized. It is to beunderstood that not necessarily all such advantages may be achieved inaccordance with any particular embodiment of the invention. Thus, forexample, those skilled in the art will recognize that the inventionsdisclosed herein may be embodied or carried out in a manner thatachieves one advantage or group of advantages as taught herein withoutnecessarily achieving other advantages as may be taught or suggestedherein. Further, the foregoing is intended to summarize certaindisclosed inventions and is not intended to limit the scope of theinventions disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section view schematically illustrating a root canalsystem of a tooth.

FIG. 2A schematically illustrates an example of a system for treating atooth with a pressure wave generator.

FIGS. 2B-1 and 2B-2 are graphs that schematically illustrate possibleexamples of acoustic power that could be generated by differentembodiments of the pressure wave generator.

FIGS. 3A, 3B, and 3C schematically illustrate examples of fluidplatforms that can be used in endodontic procedures.

FIGS. 4A, 4B, 4C, and 4D schematically illustrate examples of systemsfor endodontic procedures.

FIGS. 5A and 5B schematically illustrate examples of dental proceduresin which the treatment fluid includes dissolved gases such that bubblesin the treatment fluid can come out of solution and block smallpassageways in the tooth.

FIGS. 5C and 5D schematically illustrate examples of dental proceduresin which the treatment fluid comprises a degassed fluid that has areduced dissolved gas content (compared with the treatment fluid in theexamples of FIGS. 5A and 5B) such that the passageways of the tooth aresubstantially free of bubbles released from the treatment fluid.

FIGS. 6A and 6B are block diagrams schematically illustratingembodiments of a system adapted to produce a high-velocity liquid jet(FIG. 6A) and to provide fluid to a fluid platform (FIG. 6B).

FIG. 7 is a side view schematically illustrating an embodiment of ahandpiece comprising an embodiment of a guide tube for delivery of theliquid jet to a portion of a tooth.

FIG. 8 is a side view schematically illustrating an embodiment of adistal end of a handpiece comprising an embodiment of a guide tube fordelivering a liquid jet.

FIG. 9 schematically illustrates an example of a handpiece comprising apressure wave generator comprising a liquid jet device. The handpiececomprises a fluid outlet, and the pressure wave generator provides afluid inlet (the liquid jet).

FIG. 10A is a cross-section view that schematically illustrates anexample of a fluid platform that can be applied to a tooth using aclamp. The fluid platform comprises a pressure wave generator (e.g.,liquid jet) and a vented fluid outlet.

FIG. 10B is a top view that schematically illustrates an example of afluid platform that can be attached to the tooth with a rubber damclamp. A fluid inlet and fluid outlet are shown.

FIG. 11 schematically illustrates an alternative example of a fluidplatform that can be applied to a tooth under treatment and held inplace with pressure applied by the patient's opposing tooth.

FIG. 12A schematically illustrates embodiments of a handpiece thatincludes flow restrictors, which can include, for example, spongesand/or vents.

FIG. 12B is a top view that schematically illustrates an examplearrangement of vents in a handpiece.

FIG. 13A schematically illustrates an access opening formed in a tooth.

FIG. 13B schematically illustrates an embodiment of a tooth seal appliedto a perimeter of a crown of the tooth of FIG. 13A. The upper surface ofthe tooth seal can be made substantially flat after application andremoval of a flat plate.

FIG. 13C schematically illustrates an embodiment of a tooth seal appliedto a tooth in which a portion of the crown is missing due to decay. Thetooth seal can be used to cover or build up the portion of the crown sothat the tooth seal (and the non-decayed portion of the crown) form asubstantially complete chamber for fluid treatments.

FIG. 14A schematically illustrates an example of a sizer inserted into apulp chamber of an example tooth. In this example, the sizer is toolarge for the pulp chamber.

FIG. 14B schematically illustrates another example of a sizer insertedinto the pulp chamber of a tooth. In this example, the sizer is thecorrect size for the pulp chamber. The sizer can be moved laterallyacross the width of the chamber, with the solid lines showing the sizerin a first position and the dotted lines showing the sizer in adifferent position in the pulp chamber.

FIGS. 15A, 15B, and 15C schematically illustrate a handpiece applied toa tooth seal on a tooth. FIG. 15A is a side view, FIG. 15B is a partialcutaway view that shows a pressure wave generator disposed in the toothchamber, and FIG. 15C is a close-up view showing the distal end of thehandpiece and the pressure wave generator.

FIGS. 16A, 16B, 16C, and 16D are flowcharts illustrating examples oftechniques that may be used during various endodontic procedures.

FIG. 17 is a flowchart illustrating an example method of using adegassed fluid during an endodontic procedure.

Throughout the drawings, reference numbers may be re-used to indicate ageneral correspondence between referenced elements. The drawings areprovided to illustrate example embodiments described herein and are notintended to limit the scope of the disclosure.

DETAILED DESCRIPTION

The present disclosure describes apparatus, methods, and compositionsfor performing dental procedures such as, e.g., endodontic procedures.The disclosed apparatus, methods, and compositions advantageously may beused with root canal cleaning treatments, for example, to efficientlyremove organic and/or inorganic matter from a root canal system and/orto disinfect the root canal system. The apparatus, methods, andcompositions may be used for other dental treatments such as, e.g.,tooth cleaning, treatment of dental caries, removal of calculus andplaque, etc. Organic material (or organic matter) includes organicsubstances typically found in healthy or diseased teeth or root canalsystems such as, for example, soft tissue, pulp, blood vessels, nerves,connective tissue, cellular matter, pus, and microorganisms, whetherliving, inflamed, infected, diseased, necrotic, or decomposed. Inorganicmatter includes calcified tissue and calcified structures, which arefrequently present in the root canal system.

FIG. 1 is a cross section schematically illustrating an example of atypical human tooth 10, which comprises a crown 12 extending above thegum tissue 14 and at least one root 16 set into a socket (alveolus)within the jaw bone 18. Although the tooth 10 schematically depicted inFIG. 1 is a molar, the apparatus and methods described herein may beused on any type of human or animal tooth such as an incisor, a canine,a bicuspid, a pre-molar, or a molar. The hard tissue of the tooth 10includes dentin 20 which provides the primary structure of the tooth 10,a very hard enamel layer 22 which covers the crown 12 to a cementoenameljunction 15 near the gum 14, and cementum 24 which covers the dentin 20of the tooth 10 below the cementoenamel junction 15.

A pulp cavity 26 is defined within the dentin 20. The pulp cavity 26comprises a pulp chamber 28 in the crown 12 and a root canal space 30extending toward an apex 32 of each root 16. The pulp cavity 26 containsdental pulp, which is a soft, vascular tissue comprising nerves, bloodvessels, connective tissue, odontoblasts, and other tissue and cellularcomponents. The pulp provides innervation and sustenance to the tooth 10through the epithelial lining of the pulp chamber 28 and the root canalspace 30. Blood vessels and nerves enter/exit the root canal space 30through a tiny opening, the apical foramen 34, near a tip of the apex 32of the root 16.

I. Overview of Examples of Systems for Endodontic Treatments

A. Examples of Pressure Wave Generators

FIG. 2A schematically illustrates an example of a system for treating atooth 10 with a pressure wave generator 64. An endodontic access openingcan be formed into the tooth 10, for example, on an occlusal surface, abuccal surface, or a lingual surface. The access opening provides accessto a portion of the pulp cavity 26 of the tooth 10. The system caninclude a fluid retainer 66 and the pressure wave generator 64. Thepressure wave generator 64 can be electrically connected to a source ofelectrical power by an electrical lead 62.

The fluid retainer 66 can comprise a cap 70 and a flow restrictor 68that inhibits flow of fluid from the tooth 10. The flow restrictor 68may also inhibit flow of air into the tooth 10. The cap 70 may be formedfrom a sufficiently durable, biocompatible substance such as metal orplastic. The flow restrictor 68 may include a sponge, a membrane(permeable or semi-permeable), or a vent. The flow restrictor 68 maylimit fluid pressure in the tooth 10 such that if the fluid pressurerises above a threshold, fluid can leak or flow from the tooth chamberthrough the flow restrictor 68. The use of a flow restrictor 68advantageously may prevent fluid pressure in the tooth chamber (e.g., inthe pulp chamber 28 or at the apex 32 of the tooth) from rising toundesirable or unsafe levels. Fluids as described herein generally meansliquids, and the liquids may include a certain amount of dissolved gas.For example, a fluid can include water (having a normal dissolved gas(e.g., air) content as can be determined from Henry's law for theappropriate temperature and pressure conditions) or degassed water,which can have a reduced dissolved gas content as compared to water witha normal dissolved gas content.

The fluid retainer 66 may include a handpiece (not shown) by which adental practitioner can apply or maneuver the fluid retainer 66 relativeto the tooth 10 during treatment. In some implementations, the fluidretainer 66 can be applied to the tooth with a mechanical clasp or clamp(see, e.g., FIGS. 10A and 10B), a dental adhesive, or by pressureapplied by the patient by biting on the retainer (see, e.g., FIG. 11).

The fluid retainer 66 may be configured to be applied to the tooth, forexample, by placing the retainer on an occlusal surface of the tooth(with or without an adhesive or flow restrictor such as a sponge), bycovering or plugging an access opening to the tooth chamber, by wrappinga portion of the fluid retainer around the tooth, etc. For example,although FIG. 2A shows the fluid retainer 66 placed over the occlusalsurface of the tooth 10, in other embodiments the distal end of thefluid retainer 66 is sized or shaped to fit into the access opening,e.g., as a plug.

As schematically illustrated in FIG. 2A, a distal end of the pressurewave generator 64 can be disposed in the fluid in a tooth chamber 65 inthe tooth (sometimes the tooth chamber 65 may be referred to herein as atooth cavity). The tooth chamber 65 may include at least a portion ofany space, opening, or cavity of the tooth 10, including any portion ofspaces, openings, or cavities already present in the tooth 10 (either bynormal or abnormal dentin and/or tissue structure or by degeneration,deterioration, or damage of such structure) and/or any portion ofspaces, openings, or cavities formed by a dental practitioner during atreatment. For example, the tooth chamber 65 may include at least aportion of the pulp chamber 28 and may also include at least a portionof one or more of the following: an access opening to the tooth, a rootcanal space 30, and a tubule. In some treatments, the tooth chamber 65can include some or all of the root canal spaces 30, accessory canals,and tubules in the tooth 10. In some treatments, the access opening canbe formed apart or separately from the tooth chamber.

The distal end of the pressure wave generator 64 may be disposed in thetooth chamber, for example, in the pulp chamber 28. The distal end ofthe pressure wave generator 64 may be sized or shaped to fit in thetooth chamber. For example, the distal end of the pressure wavegenerator may be sized to fit in or through an endodontic access openingformed in the tooth. In some treatment methods, the distal end of thepressure wave generator 64 may be disposed within a few millimeters ofthe floor of the pulp chamber 28 (see, e.g., FIG. 15C). In othermethods, the distal end of the pressure wave generator 64 can bedisposed in the fluid retained by the fluid retainer 66, but outside thepulp cavity 26 (e.g., beyond the occlusal surface of the tooth). In someimplementations, the pressure wave generator 64 (in addition to or as analternative to the fluid retainer 66) may be coupled to a handpiece orportable housing that may be maneuvered in the mouth of the patient soas to position or orient the pressure wave generator 64 relative to adesired tooth under treatment.

The distal end of the pressure wave generator 64 may be submerged influid in the tooth chamber during at least a portion of the endodonticprocedure. For example, the distal end of the pressure wave generator 64may be disposed in the tooth chamber 65 while there is little or notliquid in the tooth chamber. Fluid can be added to the tooth chambersuch that a fluid level rises above the distal end of the generator 64.The pressure wave generator 64 may then be activated for at least aportion of the endodontic procedure. During other portions of theprocedure, the generator 64 may be inactive and/or above the fluid levelin the tooth chamber 65.

In various implementations, the pressure wave generator 64 comprises oneor more embodiments of the various apparatus described herein. Forexample, the pressure wave generator 64 can include a liquid jet device.In some embodiments, the liquid jet device comprises a positioningmember (e.g., a guide tube) having a channel or lumen along which orthrough which a liquid jet can propagate. The distal end portion of thepositioning member may include an impingement surface on which theliquid jet impinges and is deflected into jets or spray. The distal endportion of the positioning member may include one or more openings thatpermit the jet to interact with the fluid in the surrounding environment(e.g., fluid in the tooth chamber) and also permit the deflected liquidto exit the positioning member and interact with the surroundingenvironment in the tooth 10 (e.g., the tooth chamber and the fluid inthe tooth chamber). The result of these interactions can be generationof pressure waves and fluid circulation in the tooth chamber 65, whichcan at least partially clean the tooth. In some treatment methods, theopenings disposed at or near the distal end portion of the positioningmember are submerged in fluid retained in the tooth 10 by the fluidretainer 66. As will be further described below with reference to FIG.3A, in some such embodiments the liquid jet device may function as afluid inlet 71 to the tooth chamber 65 and may deliver fluid to at leastpartially fill the chamber. Accordingly, in some such embodiments, theliquid jet device functions as a pressure wave generator 64 and as afluid inlet 71.

In some embodiments, the pressure wave generator 64 may include a sonic,ultrasonic, or megasonic device (e.g., a sonic, ultrasonic, or megasonicpaddle, horn, or piezoelectric transducer), a mechanical stirrer (e.g.,a motorized propeller or paddle or rotating/vibrating/pulsating disk orcylinder), an optical system that can provide optical energy to thetooth chamber 65 (e.g., an optical fiber that propagates laser lightinto the tooth chamber), or any other device that can cause a pressurewave to be generated in the tooth or in a propagation medium in thetooth (e.g., the fluid retained in a tooth chamber).

In some embodiments, the cap 70 is not used. For example, the flowrestrictor 68 may be applied to the occlusal surface of the tooth 10around or over the access opening, and the distal end of the pressurewave generator 64 can be inserted into the tooth chamber 65 through theflow restrictor 68 (or an opening in the flow restrictor).

(1) Examples of Acoustic Cavitation Produced by the Pressure WaveGenerator

The pressure wave generator 64 can be configured to generate an acousticwave 67 that can propagate through the tooth and/or the fluid in thetooth chamber 65 and can detach or dissolve organic and/or inorganicmaterial from dentinal surfaces and/or dissociate pulpal tissue. Thefluid in the tooth chamber 65 can act as a propagation medium for theacoustic wave 67 and can help propagate the acoustic wave 67 toward theapex 32 of the root canal space 30, into tubules, and into other spacesin the tooth where organic matter may be found. The acoustic wave 67 maycause or increase the efficacy of various effects that may occur in thetooth 10 including, but not limited to, acoustic cavitation (e.g.,cavitation bubble formation and collapse, inertial cavitation, microjetformation), acoustic streaming, microerosion, fluid agitation, fluidcirculation, vorticity, sonoporation, sonochemistry, and so forth. Theacoustic energy may be sufficient to cause organic and/or inorganicmaterial in the tooth to be detached from surrounding dentin. It isbelieved (although not required) that the effects caused (or enhanced)by the acoustic energy may lead to a cleaning action that delaminates ordetaches the pulpal tissue from the root canal wall, dentinal surfaces,and/or tubules, and may further break such tissue down into smallerpieces.

Without subscribing to or being limited by any particular theory or modeof operation, the acoustic field generated by the pressure wavegenerator 64 may generate a cavitation cloud within the fluid retainedin the tooth chamber 65. The creation and collapse of the cavitationcloud (and/or the jet impacting the impingement surface) may, in somecases, generate a substantial hydroacoustic field in the tooth 10. Thisacoustic field may generate pressure waves, oscillations, and/orvibrations in or near the canal spaces of the tooth and/or interiordentinal surfaces, which are filled with dentinal tubules. Furthercavitation effects may be possible, including growth, oscillation, andcollapse of cavitation bubbles formed in or near the tubules (e.g.,possibly at the high surface-energy sites of the tubules). These (and/orother) effects may lead to efficient cleaning of the pulp chamber 28 ofthe tooth.

(2) Examples of Acoustic Power Generated by Pressure Wave Generators

FIGS. 2B-1 and 2B-2 are graphs that schematically illustrate possibleexamples of acoustic power that could be generated by differentembodiments of the pressure wave generator. These graphs schematicallyshow acoustic power (in arbitrary units) on the vertical axis as afunction of acoustic frequency (in kHz) on the horizontal axis. Theacoustic power in the tooth may influence, cause, or increase thestrength of effects including, e.g., acoustic cavitation (e.g.,cavitation bubble formation and collapse, microjet formation), acousticstreaming, microerosion, fluid agitation, fluid circulation,sonoporation, sonochemistry, and so forth, which may act to dissociateorganic material in the tooth 10 and effectively clean the pulp cavity26 and/or the canal spaces 30. In various embodiments, the pressure wavegenerator 64 may produce an acoustic wave 67 including acoustic power(at least) at frequencies above: about 0.5 kHz, about 1 kHz, about 10kHz, about 20 kHz, about 50 kHz, about 100 kHz, or greater. The acousticwave 67 may have acoustic power at other frequencies as well (e.g., atfrequencies below the aforelisted frequencies).

The graph in FIG. 2B-1 represents a schematic example of acoustic powergenerated by a liquid jet impacting a surface disposed in a toothchamber 65 and by the interaction of the liquid jet with fluid in thetooth chamber. This schematic example shows a broadband spectrum 190 ofacoustic power with significant power extending from about 1 kHz toabout 1000 kHz (e.g., the bandwidth may about 1000 kHz). The bandwidthof the acoustic energy spectrum may, in some cases, be measured in termsof the 3-decibel (3-dB) bandwidth (e.g., the full-width at half-maximumor FWHM of the acoustic power spectrum). In various examples, abroadband acoustic power spectrum may include significant power in abandwidth in a range from about 1 kHz to about 500 kHz, in a range fromabout 10 kHz to about 100 kHz, or some other range of frequencies. Insome implementations, a broadband spectrum may include acoustic powerabove about 1 MHz. In some embodiments, the pressure wave generator 64can produce broadband acoustic power with peak power at about 10 kHz anda bandwidth of about 100 kHz. In various embodiments, the bandwidth of abroadband acoustic power spectrum is greater than about 10 kHz, greaterthan about 50 kHz, greater than about 100 kHz, greater than about 250kHz, greater than about 500 kHz, greater than about 1 MHz, or some othervalue. In some cleaning methods, acoustic power between about 20 kHz and200 kHz may be particularly effective. The acoustic power may havesubstantial power at frequencies greater than about 1 kHz, greater thanabout 10 kHz, greater than about 100 kHz, or greater than about 500 kHz.Substantial power can include, for example, an amount of power that isgreater than 10%, greater than 25%, greater than 35%, or greater than50% of the total acoustic power (e.g., the acoustic power integratedover all frequencies).

The graph in FIG. 2B-2 represents a schematic example of acoustic powergenerated by an ultrasonic transducer disposed in a tooth chamber 65.This schematic example shows a relatively narrowband spectrum 192 ofacoustic power with a highest peak 192 a near the fundamental frequencyof about 30 kHz and also shows peaks 192 b near the first few harmonicfrequencies. The bandwidth of the acoustic power near the peak is about5 to 10 kHz, and can be seen to be much narrower than the bandwidth ofthe acoustic power schematically illustrated in FIG. 2B-1. In otherembodiments, the bandwidth of the acoustic power can be about 1 kHz,about 5 kHz, about 10 kHz, about 20 kHz, about 50 kHz, about 100 kHz, orsome other value. The acoustic power of the example spectrum 192 hasmost of its power at the fundamental frequency and first few harmonics,and therefore the ultrasonic transducer of this example may provideacoustic power at a relatively narrow range of frequencies (e.g., nearthe fundamental and harmonic frequencies). The acoustic power of theexample spectrum 190 exhibits relatively broadband power (with arelatively high bandwidth compared to the spectrum 192), and the exampleliquid jet may provide acoustic power at significantly more frequenciesthan the example ultrasonic transducer.

It is believed, although not required, that acoustic waves havingbroadband acoustic power (see, e.g., the example shown in FIG. 2B-1) maygenerate cavitation that is more effective at cleaning teeth thancavitation generated by acoustic waves having a narrowband acousticpower spectrum (see, e.g., the example shown in FIG. 2B-2). For example,a broadband spectrum of acoustic power may produce a relatively broadrange of bubble sizes in the cavitation cloud, and the implosion ofthese bubbles may be more effective at disrupting tissue than bubbleshaving a narrow size range. Relatively broadband acoustic power may alsoallow acoustic energy to work on a range of length scales, e.g., fromthe cellular scale up to the tissue scale. Accordingly, pressure wavegenerators that produce a broadband acoustic power spectrum (e.g., someembodiments of a liquid jet) may be more effective at tooth cleaning forsome endodontic treatments than pressure wave generators that produce anarrowband acoustic power spectrum. In some embodiments, multiplenarrowband pressure wave generators may be used to produce a relativelybroad range of acoustic power. For example, multiple ultrasonic tips,each tuned to produce acoustic power at a different peak frequency, maybe used.

B. Examples of Fluid Platforms for Fluid Management

Some apparatus and methods disclosed herein may perform more efficientlyif at least a portion of the pulp cavity 26 of the tooth 10 undertreatment is filled with fluid (e.g., liquid) during an endodonticprocedure. In some such treatment methods, the pulp chamber 28 may besubstantially filled with liquid with substantially no air (or gas)pockets remaining in the pulp chamber 28. For example, leakage of airinto the pulp chamber 28 may reduce the effectiveness of the treatmentin some circumstances (e.g., by reducing the effectiveness of cavitationand damping the pressure waves). In some treatment methods, leakage ofthe fluid from the pulp chamber 28 into the oral cavity (e.g., mouth) isnot desired as such leakage may leave an unpleasant taste or smell ormay lead to damaged tissues in the patient's mouth. Accordingly, invarious treatment methods, a fluid platform can be used that maintains asubstantially liquid-filled pulp chamber 28, inhibits leakage of airinto the pulp chamber 28 during treatment, and/or inhibits leakage oftreatment fluid, waste fluid, and/or material from the pulp cavity intothe mouth of the patient.

The fluid platform 61 (e.g., a fluid retainer) can be used formaintaining fluid in a tooth chamber 65 in a tooth, which mayadvantageously enable cleaning of a root canal space 30 (or otherportions of the tooth. In some procedures, fluid is delivered to thetooth chamber 65, and the fluid pressure in the tooth chamber 65 mayrise. If the fluid pressure in the chamber becomes too great, organicmaterial, fluid, etc. may be forced through the apex 32 of the tooth 10,which may lead to complications such as infection. Also, if for exampledue to suction negative pressure is created inside the tooth chamber,and if the absolute magnitude of the negative pressure is large enough,the negative pressure may cause problems such as pain and discomfort forthe patient. Thus, in various embodiments, the fluid platform 61 isconfigured such that the pressure created at the apex 32 of the tooth 10(or in a portion of the tooth chamber such as, e.g., the pulp chamber28) is below an upper value of: about 500 mmHg, about 300 mmHg, about200 mmHg, about 100 mmHg, about 50 mmHg, about 30 mmHg, about 20 mmHg,or some other value. (Note: 1 mmHg is one millimeter of mercury and is ameasure of pressure equal to about 133.322 Pascal). Embodiments of thefluid platform can be configured so that if the fluid pressure in thetooth chamber 65 rises above an upper threshold, fluid can flow or leakfrom the chamber to maintain the fluid pressure at a safe or desiredlevel. The threshold can be a predetermined pressure level. Certainpredetermined pressure levels can be about 500 mmHg, about 300 mmHg,about 200 mmHg, about 100 mmHg, about 50 mmHg, about 30 mmHg, or about20 mmHg.

In some implementations, it may be desired that the apical pressure ortooth chamber pressure be greater than a lower value of: about −1000mmHg, about −500 mmHg, about −300 mmHg, about −200 mmHg, about −100mmHg, about −50 mmHg, about 0 mmHg, or some other value. For example, ifthe pressure becomes too low (too negative), the patient may experiencediscomfort. Embodiments of the fluid retainer can be configured so thatif the fluid pressure in the tooth chamber 65 decreases below a lowerthreshold, ambient air can flow or be drawn through a flow restrictor(e.g., a sponge or vent) to maintain the fluid pressure above apatient-tolerable or desired level. The lower threshold can be apredetermined pressure level. Certain predetermined pressure levels canbe about −1000 mmHg, about −500 mmHg, about −300 mmHg, about −200 mmHg,about −100 mmHg, about −50 mmHg, about or 0 mmHg. Thus, variousembodiments of the fluid retainer can self-regulate the pressure in thetooth chamber to be below a first (e.g., upper) threshold and/or above asecond (e.g., lower) threshold. As discussed, either or both thresholdscan be a predetermined pressure level.

The fluid pressure in the tooth chamber 65 may fluctuate with time asfluid flows in and out of the chamber and/or as a pressure wavegenerator 64 is activated to generate acoustic waves 67 (which comprisepressure oscillations). The acoustic waves 67 may induce cavitation,which can cause pressure fluctuations as well. In some implementations,a mean or average pressure may be used. The mean pressure can be a timeaverage of the pressure (at a particular point in the fluid) over a timeperiod corresponding to the pressure fluctuations occurring in thefluid, or in some contexts, a spatial average of the pressure over aspatial region (e.g., over some or all of the tooth chamber). Thepressure at a given point (in space or time) may be much larger than themean pressure (e.g., due to a cavitation-induced event), and certainembodiments of the fluid platform may provide safety features to inhibitthe rise of pressure above an undesired or unsafe threshold (e.g., byproviding a vent to allow liquid to flow from the tooth chamber).

In various treatment methods, when a fluid is delivered into a toothchamber 65 of a tooth 10, management of the fluid in the tooth chamber65 can be “controlled” or left “uncontrolled.”

(1) Examples of Uncontrolled Fluid Platforms

In some types of uncontrolled fluid platforms, the tooth chamber 65(e.g., a portion of the pulp cavity) may be substantially open toambient air, fluids, etc., and the fluid inside the tooth chamber 65 maynot be fully contained in the tooth chamber 65. For example, the fluidmay splash, overflow, or be evacuated via an external system (e.g., asuction wand) during the dental procedure. In some such cases, the fluidcan be replenished intermittently or continuously during the procedure(e.g., via irrigation or syringing). The excess waste fluid also may beevacuated from the patient's mouth or from a rubber dam (if used)intermittently or continuously during the procedure.

An example of an uncontrolled method of fluid management can be theirrigation of the root canals with endodontic irrigation syringes.During this procedure, the fluid is injected into and exits from thepulp cavity, flowing into the oral space or a rubber dam (if used)and/or is suctioned by an external evacuation system operated by dentalassistant. Another example of uncontrolled fluid management can beactivation of the irrigation fluid by ultrasonic tips that can beinserted into the root canals. Upon activation of the ultrasonic device,the fluid in the tooth may splash out of the pulp cavity. The fluidinside the pulp cavity can be replenished via a syringe or the waterlineof the ultrasonic tip, and the excess fluid may be suctioned from theoral space or the rubber dam (if used) via an external suction hoseoperated by a dental assistant.

(2) Examples of Controlled Fluid Platforms

Another type of fluid platform can be categorized as a “controlled”fluid platform. In some types of controlled fluid platforms, the fluidcan be substantially contained in the tooth chamber 65 (e.g., pulpcavity) by using an apparatus to at least partially cover an endodonticaccess opening. Some such fluid platforms may or may not include fluidinlets and/or outlets for the fluid to enter and exit the tooth chamber65, respectively. Fluid flowing in and/or out of the tooth 10 during aprocedure can be controlled. In some embodiments, the total volume (orrate) of fluid going into the tooth 10 can be controlled to besubstantially equal to the total volume (or rate) of fluid going out ofthe tooth 10. Examples of two types of controlled fluid platforms willbe described.

(i) Examples of Closed Fluid Platforms

A closed system can be a controlled system where the amount of fluidflowing into the tooth chamber 65 substantially equals the amount offluid exiting the tooth chamber 65. An example of a closed systemincludes a fluid cap 70 that is applied or sealed to the tooth 10,around the endodontic opening. In some such systems, the fluid's drivingforce (e.g., a pressure differential) is applied to only one of theopenings (e.g., either inlet or outlet). In other implementations, thedriving force can be applied at both the inlet and the outlet, in whichcase the applied driving forces may be regulated to be substantiallyequal in magnitude in order to reduce or avoid the following possibleproblems: exerting pressure (positive or negative) onto the tooth 10which may result in extrusion of fluid/debris periapically (e.g.,positive pressure) or causing pain and/or bleeding due to excessivenegative pressure, or breaking the seal of the fluid platform causingleakage of fluid and organic matter into the mouth (e.g., positivepressure) or drawing air into the chamber (e.g., negative pressure)which can reduce the treatment efficiency.

The operation of some closed fluid platforms can be relatively sensitivedue to the regulation of the inlet and outlet fluid pressures to besubstantially the same. Some such closed systems may lead to safetyissues for the patient. For example, some such implementations may notensure a substantially safe pressure that the patient's body cantolerate (e.g., apical pressures in a range from about −30 mmHg to +15mmHg, or −100 mmHg to +50 mmHg, or −500 mmHg to +200 mmHg, in variouscases). Some such closed systems can result in exertion of pressure(negative or positive) inside the tooth. For instance, if the drivingforce corresponds to the pressure at the inlet, a small obstruction onthe outlet fluid line (which inhibits or reduces outflow of fluid fromthe tooth chamber) can result in increased pressure inside the tooth 10.Also, the elevation at which the waste fluid is discharged with respectto the tooth can cause static pressures inside the tooth 10.

(ii) Examples of Vented Fluid Platforms

Examples of a vented fluid platform include controlled systems where theinlet fluid flow rate and exit fluid flow rate may, but need not be,substantially the same. The two flow rates may in some cases, or forsome time periods, be substantially the same. The fluid platform mayinclude one or more “vents” that permit fluid to leave the tooth chamber65, which can reduce the likelihood of an unsafe or undesired increasein fluid pressure (e.g., pressure at the periapical region). In somevented fluid platforms, the inlet and outlet flow rates may be driven byindependent driving forces. For example, in some implementations, thefluid inlet can be in fluid communication with and driven by a pressurepump, while a fluid outlet can be in fluid communication with andcontrolled via an evacuation system (e.g., a suction or vacuum pump). Inother implementations, the fluid inlet or outlet can be controlled witha syringe pump. The pressures of the fluid inlet and the fluid outletmay be such that a negative net pressure is maintained in the toothchamber 65. Such a net negative pressure may assist delivering thetreatment fluid into the tooth chamber 65 from the fluid inlet.

In various embodiments described herein, the “vents” can take the formof a permeable or semi-permeable material (e.g., a sponge), openings,pores, or holes, etc. The use of vents in a controlled fluid platformmay lead to one or more desirable advantages. For example, theevacuation system can collect waste fluid from the tooth chamber 65, aslong as there is any available. If there is a pause in treatment (e.g.the time between treatment cycles), waste fluid flow may stop, and theevacuation system may start drawing air through the one or more vents toat least partially compensate for the lack of fluid supplied to theevacuation system, rather than depressurizing the tooth chamber 65. Ifthe evacuation system stops working for any reason, the waste fluid mayflow out through the one or more vents into the patient's mouth or ontoa rubber dam (if used), where it can be collected by an externalevacuation line. Therefore, the use of vent(s) can tend to dampen theeffects of the applied pressure differential, and therefore may inhibitor prevent negative or positive pressure buildup inside the tooth.Certain embodiments of vented fluid platforms may provide increasedsafety since the system can be configured to maintain a safe operatingpressure in the tooth, even when the operating parameters deviate fromthose specified. Also note that positive or negative pressure inside thetooth chamber 65 can exert some amount of force on the sealingmaterial(s), and as such a stronger seal may be required to withstandsuch force in some cases. Possible advantages of some vented systemsinclude that the vent(s) help relieve pressure increases (or decreases)inside the tooth, reduce or eliminate the forces acting on the sealingmaterial(s), and therefore render the sealing more feasible andeffective.

FIG. 3A schematically illustrates an example of a fluid platform 61 thatcan be used in an endodontic procedure. In this example, the fluidplatform 61 includes a fluid retainer 66 (e.g., cap 70 and flowrestrictor 68) that can be generally similar to those described withreference to FIG. 2A. The fluid retainer 66 may be used to retain fluidin a chamber in the tooth 10. The fluid retainer 66 may include aninternal (or inner) chamber 69 such that when the fluid retainer 66 isapplied to the tooth, the internal chamber 69 and the tooth chamber 65together form a fluid chamber 63. The fluid chamber 63 may be at leastpartially filled with fluid. In some advantageous embodiments, the fluidchamber 63 may be substantially or completely filled with fluid during atreatment procedure. The flow restrictor 68, which can function as thevent described above, may be used to permit fluid to flow from thechamber 63 (e.g., if the fluid pressure in the chamber becomes toolarge) and/or to inhibit flow of air into the chamber 63. The flowrestrictor 68 can help retain fluid in the tooth chamber which mayassist promoting fluid circulation in the tooth chamber, which mayincrease the effectiveness of irrigation or cleaning. The flowrestrictor 68 can comprise a sponge (e.g., an open-cell or closed-cellfoam) in some embodiments. An example of a flow restrictor 68 comprisingan opening or port in the fluid platform 61 will be described withreference to FIG. 3B.

The fluid platform 61 also can include a fluid inlet 71 for deliveringfluid to the chamber 63 in the tooth 10. The fluid inlet 71 can have adistal end that may be configured to be submerged in the fluid in thechamber 63 (after the chamber substantially fills with fluid). Thedistal end of the fluid inlet 71 may be sized and shaped so that it canbe disposed in the pulp chamber 28 of the tooth 10, for example as shownin FIG. 3A. The distal end of the inlet 71 may be disposed within thepulp chamber 28 and above the entrances to the root canal spaces 30.Thus, in some such implementations, the fluid inlet 71 does not extendinto the canal spaces. In other implementations, the distal end of theinlet 71 may be disposed in the fluid retained by the fluid retainer 66,but outside the pulp cavity 26 (e.g., above the occlusal surface of thetooth). In some cases, the distal end of the fluid inlet 71 can besized/shaped to fit in a portion of a root canal space 30. For example,the distal end of the inlet 71 may comprise a thin tube or needle. Invarious implementations, the inlet 71 comprises a hollow tube, lumen, orchannel that delivers the fluid to the tooth chamber 65. In otherimplementations, the fluid inlet 71 may be a liquid beam (e.g., ahigh-velocity liquid jet) that is directed into the tooth chamber 65. Insome such embodiments, the liquid beam may deliver fluid to the toothchamber 65 as well as generate pressure waves 67 in the fluid in thechamber 63.

In some embodiments, the fluid platform 61 can include a fluidintroducer configured to supply fluid from a liquid source to the toothchamber. The fluid introducer may comprise embodiments of the fluidinlet 71. In some implementations, the fluid introducer can also includea fluid line (or tubing) that provides fluidic communication between thefluid introducer and the liquid source. The fluid introducer may includea portion of a liquid jet device in some implementations.

The fluid inlet 71 may be in fluid communication with a fluid reservoir,supply, or source that provides the fluid to be delivered to the toothvia the inlet 71. The fluid may be delivered under pressure, forexample, by use of one or more pumps or by using a gravity feed (e.g.,by raising the height of the fluid reservoir above the height of thetooth chamber 65). The fluid platform 61 may include additionalcomponents (not shown in FIG. 3A) including, e.g., pressure regulators,pressure sensors, valves, etc. In some cases, a pressure sensor may bedisposed in a tooth chamber 65, to measure the pressure in the toothchamber 65 during treatment.

The flow of fluid from the inlet 71 may cause or augment fluid movementin the tooth chamber 65. For example, under various conditions of fluidinflow rate, pressure, inlet diameter, and so forth, the flow that isgenerated may cause (or augment) circulation, agitation, turbulence,etc. in the tooth chamber 65, which may improve irrigation or cleaningeffectiveness in some cases. As described above, in some implementationsa liquid jet device can be used to function as the inlet 71 and candeliver fluid to the tooth chamber 65 as well as generate pressure waves67 in the chamber 65. Thus, the liquid jet device can serve as thepressure wave generator 64 and the fluid inlet 71 in suchimplementations. The fluid from the liquid jet (as well as itsconversion to a spray if an impingement plate is used) can inducecirculation in the tooth chamber 65. The flow of fluid from the inlet 71can be used for a number of processes such as irrigation, cleaning, ordisinfecting the tooth.

FIG. 3B schematically illustrates another example of a fluid platform 61that can be used in an endodontic procedure. In this example, the fluidplatform 61 comprises the fluid retainer 66, the fluid inlet 71, and afluid outlet 72 configured to remove fluid from the tooth chamber 65. Inthe illustrated embodiment, the fluid retainer 66 comprises the cap 70that can be applied or attached to a tooth seal formed on the tooth (atooth seal 75 will be described below with reference to FIGS. 13B and13C). An (optional) flow restrictor 68 comprising elastic material(e.g., a sponge or semi-permeable material) can be disposed within thegap to assist in providing a substantially water tight seal between thecap 70 and the tooth seal 75. The substantially water tight seal helpsretain fluid within the tooth chamber 65 during treatment and may alsoinhibit ambient air from entering the tooth chamber 65 during treatment.

In some implementations the fluid outlet 72 functions passively, forexample, the fluid moves through the outlet 72 because of capillaryforces, gravity, or a slight overpressure created in the tooth. In otherimplementations, the fluid outlet 72 is actively pumped, and the fluidcan be transferred using a pump, suction, or other device that drawsfluid out through the outflow conduit. In one example, the fluid outlet72 comprises a suction line operated under partial vacuum pressure tosuction out fluid and may be connected to the suction system/vacuumlines commonly found in a dental office.

As described above with reference to FIG. 3A, fluid may be at leastpartially retained in the fluid chamber 63, which can comprise theinternal chamber 69 in the fluid retainer 66 and the tooth chamber 65.The fluid chamber 63 may be at least partially filled with fluid. Insome advantageous embodiments, the fluid chamber 63 may be substantiallyor completely filled with fluid during a treatment procedure. Duringtreatment, the fluid inlet 71 and the fluid outlet 72 can be in fluidcommunication with fluid retained in the fluid chamber 63. In theembodiment illustrated in FIG. 3B, both the fluid inlet 71 and the fluidoutlet 72 are in fluid communication with the fluid in the fluid chamber63, and fluid can flow into the tooth from the fluid inlet 71 (solidarrowed lines 92 a in FIG. 3B) and be removed from the tooth via thefluid outlet 72 (solid arrowed line 92 b in FIG. 3B). Note that in thisembodiment, there is a single fluid chamber 63 in which both fluiddelivered from the inlet 71 and fluid removed from the outlet 72 candirectly fluidly communicate (e.g., without passing through a valve, atube, a needle, etc.). The delivery of fluid into the tooth chamber 65via the fluid inlet 71 can cause a circulation in the tooth chamber 65(see, e.g., arrowed lines 92 a).

In this example, the fluid platform 61 comprises an additional flowrestrictor in the form of a vent 73 that is disposed along the fluidoutlet 72. The vent 73 can permit fluid from the tooth chamber 65 toflow out of the vent 73, for example if the fluid pressure becomes toolarge in the chamber. The vent 73 can act as a relief valve to inhibitover-pressurization of the tooth chamber 65.

In some embodiments, the vent 73 comprises a directionally biased valvethat permits fluid to leave the tooth chamber 65 but inhibits ambientair from entering the tooth chamber 65. For example, the vent 73 maycomprise one or more one-way (or check) valves. A one-way valve may havea cracking pressure selected to permit fluid to leave the tooth chamber65 when the fluid pressure in the tooth chamber 65 exceeds a pressurethreshold (e.g., about 100 mmHg in some cases). In other embodiments, aone-way valve may be used to permit ambient air to flow into the toothchamber 65 when the pressure differential between ambient conditions andthe pressure in the tooth chamber 65 is sufficiently large. For example,the cracking pressure of such a one-way valve may be selected such thatif the fluid pressure in the chamber is less than a net (negative)threshold (e.g., the tooth chamber is under-pressurized), the valve willopen to permit ambient air to flow into the fluid retainer 66. Suchambient air may be suctioned out of the fluid retainer 66 via a fluidoutlet 72 (e.g., the one-way valve may be disposed along the fluidoutflow line). In some embodiments, the vents 73 comprise a one-wayvalve to permit fluid to leave the fluid retainer 66 (while inhibitingambient air from entering), and a one-way valve to permit ambient air toenter the fluid retainer 66. The cracking pressures of these two one-wayvalves may be selected so that in a desired pressure range, fluid isretained in the tooth chamber 65 and ambient air is inhibited fromentering the tooth chamber 65. For example, the pressure range in thetooth may be between about −100 mmHg and +100 mmHg.

In other embodiments, the vent 73 may be configured to permit air toenter the fluid outlet 72 and be entrained with fluid removed from thetooth chamber 65. For example, as shown in FIG. 3B, the vent 73 may bepositioned and oriented such that ambient air flows into the fluidoutlet 72 in the direction of the fluid flow in the outlet 72 (see,e.g., dashed arrowed line 94 a). In such embodiments, the flow in thefluid outlet 72 includes both fluid from the tooth chamber 65 (see,e.g., solid arrowed line 92 b) and ambient air (see, e.g., dashedarrowed line 94 b). In some implementations, the vent 73 is disposednear the entry point of fluid into the outlet 72, e.g., within a fewmillimeters, which may make it easier for fluid to flow from the toothchamber 65 if the pressure therein rises too high. In variousembodiments, a plurality of vents 73 may be used such as, two, three,four, or more vents. The vents 73 may be sized, shaped, positioned,and/or oriented to allow fluid to flow from the tooth chamber 65 whileinhibiting air from entering the tooth chamber 65.

The example systems shown in FIGS. 3A and 3B can assist in inducingfluid circulation in the tooth chamber 65 due to the inflow of fluidfrom the fluid inlet 71 and/or the removal of fluid from the fluidoutlet 72 (if present). The example systems may also advantageously havepatient safety features. For example, if the fluid outlet 72 is blocked(e.g., a suction tube is kinked or the suction ceases to function), theflow of fluid into the tooth chamber 65 from the inlet 71 can lead toincreasing fluid pressures, which can lead to the level of fluid risingup into the outlet 72. The flow restrictor 68 (e.g., a sponge or a vent)can relieve the fluid pressure by allowing fluid to leave the toothchamber 65 (e.g., by flowing through the sponge or leaking out thevent). As another example, if the fluid inlet 71 is blocked (or ceasesto function), the fluid outlet 72 may remove the fluid from the toothchamber 65 and may lead to increasingly lower pressures in the toothchamber 65. The flow restrictor 68 can tend to keep the pressure in thetooth 10 at a safe or desirable level by allowing ambient air to flowinto the fluid outlet 72 to at least partially alleviate thedepressurization of the tooth chamber 65. Thus, by allowing the pressurein the tooth chamber 65 to remain within safe or desirable bounds (e.g.,above a lower pressure threshold and below an upper pressure threshold),certain such embodiments may provide advantages over closed fluidcontainers that do not include some form of fluid restrictor or pressurerelief valve.

Accordingly, certain embodiments of the fluid platform 61 may be atleast partially open to the ambient environment (e.g., via the flowrestrictor 68) and may substantially allow the pressure in the toothchamber 65 to self-regulate. An additional advantage of certain suchembodiments can be that pressure regulators, pressure sensors,inlet/outlet control valves, etc. need not be used to monitor orregulate the pressure in the tooth chamber 65 under treatment, becausethe self-regulation of the flow restrictor 68 permits the pressure toremain within desired or safe levels. In other embodiments, pressureregulators, pressure sensors, and control valves may be used to provideadditional control over the fluid environment in the tooth. For example,pressure sensor(s) could be used to measure pressure along a fluid inlet71 or a fluid outlet 72, in a portion of the tooth chamber 65, etc. Inyet other embodiments, a temperature sensor or temperature controllermay be used to monitor or regulate the temperature of the fluid in thefluid inlet 71 or a fluid outlet 72, in the tooth chamber 65, etc.

(iii) Examples of Systems for Analyzing Fluid Leaving the Tooth

Substantially anything cleaned out from the pulpal chamber (in teeththat have pulpal chambers) and canals of a tooth (including pulp,debris, organic matter, calcified structures, etc.) can be monitored todetermine the extent or progress of the tooth cleaning or to determinewhen the tooth becomes substantially clean. For example, whensubstantially no more pulp, calcified structures, organic matter,inorganic matter, and/or debris comes out of the tooth, the tooth may besubstantially clean, and the system may provide a signal (e.g.,audible/visible alarm, appropriate output on a display monitor) to theoperator to stop the procedure. Such monitoring of the output from thetooth chamber 65 can be used with any of the embodiments describedherein, including with open, closed, or vented fluid platforms.

FIG. 3C schematically illustrates an example of a fluid platform 61 inwhich the fluid outlet 72 is in fluid communication with an optionalmonitoring sensor 74. The monitoring sensor 74 can monitor or analyzeone or more properties of the fluid removed from the tooth 10. Themonitoring sensor 74 can include an optical, electrical (e.g.,resistive), chemical, and/or electrochemical sensor. Monitoring sensors74 can include a liquid particle counter (e.g., configured to determinea range of particle sizes in the fluid), a liquid or gas chromatograph,a flame ionization detector, photoionization detector, a thermalconductivity detector, a mass spectrometer, etc. The monitoring sensor74 can use elemental analysis techniques to determine properties of thefluid.

In some embodiments, the monitoring sensor includes an optical sensorsuch as, e.g., a photometric sensor, a spectroscopic sensor, a colorsensor, or a refractive index sensor. Optical properties in any part ofthe electromagnetic spectrum can be measured (e.g., ultraviolet,visible, infrared, etc.). For example, an optical sensor can include alight source (e.g., an LED) and a light detector (e.g., a photodiode)disposed relative to a fluid (e.g., fluid in the fluid outlet 72). Thelight source can emit light into the fluid and the light detector canmeasure the amount of light reflected from or transmitted through thefluid in the fluid outlet 72. At early stages of an endodontictreatment, the fluid from the tooth may contain substantial amounts ofpulpal matter such that the fluid is murky and reflects, and does nottransmit, much light. As the treatment proceeds, the amount of pulpalmatter in the fluid decreases, and the reflectivity may correspondinglydecrease (or the transmittivity may increase). When relatively littleadditional pulpal matter is contained in the fluid from the tooth, thefluid in the outlet 72 may be substantially clear, and the reflectivityor transmittivity may reach a threshold value appropriate for fluidwithout pulpal matter (e.g., for clear water). The decrease of pulpalmatter in the fluid outflow can be used as an indicator that thetreatment is substantially complete or that the tooth chamber issubstantially clean.

In some embodiments, a second monitoring sensor 74 is disposed upstreamof the fluid platform 61 and can be used to provide a baselinemeasurement of properties of the fluid prior to entering the toothchamber 65. For example, the threshold value may be based, at least inpart, on the baseline measurement. Thus, in some embodiments, when thesensed property of the fluid property leaving the fluid platform issubstantially the same as the sensed property of the fluid entering thefluid platform, it can be determined that the tooth treatment issubstantially complete.

In various embodiments, the monitoring may be done continuously duringthe treatment or may be done at discrete times during the treatment. Themonitoring sensor 74 may be configured to measure an amount of carbon inthe fluid, e.g., total organic carbon (TOC), total inorganic carbon, ortotal carbon. The amount of total inorganic carbon may reflect removalof hard structures such as calcified tissues, pulp stone, or dentin(e.g., tertiary dentin) during the treatment. The monitoring sensor 74may measure a property associated with removal of soft tissue (e.g.,pulp, bacteria), hard tissue (e.g., pulp stone or calcified tissue), orboth.

Thus when a property measured by the monitoring sensor 74 reaches athreshold value, the system can alert the operator that the treatment iscomplete (e.g., little additional organic or inorganic material is beingremoved from the tooth). In some embodiments, a change in a measuredproperty (e.g., a change between measurements at two different times)can be monitored, and when the change is sufficiently small (indicatingthat a threshold or plateau has been reached), the system can alert theoperator that treatment is complete.

In some implementations, feedback from the monitoring sensor 74 can beused to automatically adjust, regulate, or control one or more aspectsof the endodontic treatment. For example, a tooth irrigation device, atooth cleaning device, a fluid source, a fluid platform, a pressure wavegenerator, etc. may be adjusted based on the feedback to automate someor all of the treatment. In one implementation, the concentration of atissue dissolving agent (e.g., sodium hypochlorite) or a fluid flow ratecan be adjusted based at least in part on feedback for a monitoredamount of organic material in the tooth outflow. For example, if theamount of organic matter flowing from the tooth remains relatively high,the concentration of the tissue dissolving agent in the treatment fluidor the flow rate of the treatment fluid may be increased. Conversely, ifthe amount of organic matter decreases quickly, the tooth cleaning maybe nearly complete, and the concentration of the tissue dissolver or thefluid flow rate may be decreased. In some such implementations, if theorganic matter has decreased sufficiently, the system may switch to adifferent solute (e.g., a decalcifying agent) to begin a different phaseof the treatment. In another implementation, feedback from themonitoring sensor 74 can be used to adjust a pressure wave generator,for example, by increasing or decreasing the time the generator isactivated (or deactivated). In some implementations using feedback, aproportional-integral-derivative (PID) controller or a fuzzy logiccontroller can be used to regulate or control aspects of the endodontictreatment.

(iv) Additional Features of Some Controlled Fluid Platforms

In some methods, little or substantially no treatment solution isinjected through the apex 32 of the tooth 10 into the periapical regionof the tooth 10 (the tissues that surround the apex 32 of the tooth). Tolimit injection of fluid into the periapical region, some embodimentsare configured such that the pressure created inside the tooth andcommunicated to the apex 32 of the tooth 10 is equal to or lower than apressure in the periapical region of the tooth 10 that is tolerable bypatients. In various embodiments, the fluid platform 61 is configuredsuch that the pressure created at the apex 32 of the tooth 10 (or in aportion of the tooth chamber such as, e.g., the pulp chamber 28) isbelow an upper value of about 500 mmHg, about 300 mmHg, about 200 mmHg,about 100 mmHg, about 50 mmHg, about 20 mmHg, or some other value. Insome implementations, it may be desired that the apical pressure ortooth chamber pressure be above a lower value of about −1000 mmHg, about−500 mmHg, about −300 mmHg, about −200 mmHg, about −100 mmHg, about −50mmHg, about 0 mmHg, or some other value. By selecting the size, number,and/or arrangement of fluid restrictors (e.g., sponges, vents, etc.),various systems can limit the apical pressure or the tooth chamberpressure to the foregoing values or ranges, as desired.

In some embodiments, it may be beneficial for the pressure at the apex32 of the tooth 10 to be negative (e.g., lower than the pressure in theapical area). A negative pressure may allow inflamed bacteria, debris,and tissue (such as that found in a periapical lesion) to be suctionedout through the apex 32 of the tooth 10 and out of the mouth. It may beadvantageous if the negative pressures created in the apex 32 of thetooth 10 are not too high (in magnitude) as this may induce pain in thepatient. In one embodiment, the pressure created at the apex 32 of thetooth 10 is above about −1000 mmHg. In another embodiment, the pressurecreated at the apex 32 of the tooth 10 is above other values such as,e.g., about −600 mmHg, −500 mmHg, −250 mmHg, or some other value.

In some embodiments, substantially little or no treatment fluid,bacteria, tissue, debris, or chemicals enters the mouth during theprocedure (e.g., substantially no leak from the handpiece and no leakbetween the handpiece and the tooth during the procedure), which mayimprove fluid management during the procedure. Spilling little or nomaterial into the mouth during the procedure reduces the need to suctionand remove waste fluid and material during the procedure. Accordingly,an assistant may not be needed during the procedure, which may simplifylogistics and reduce manpower. Bacteria and debris removed from theinfected tooth during the procedure should be avoided from being spilledinto the mouth of the patient—so removing such material via the fluidplatform may improve the cleanliness or hygiene of the procedure.Further, many of the chemicals used during endodontic procedures (e.g.,NaOCl, etc.) may be corrosive or irritating to oral/gum tissue andreducing the likelihood of or preventing them from entering thepatient's mouth is therefore desirable. Also, many of the chemicals andsolutions used during endodontic procedures taste bad; therefore, notspilling such materials in the mouth during a procedure greatly improvespatient comfort.

Delivering substances such as chemicals, medicaments, etc. in thetreatment solution reduces the likelihood or prevents having to add suchsubstances intermittently during an endodontic procedure (e.g. addingNaOCl intermittently during a root canal procedure). Embodiments of thefluid platform can allow one or more substances to be added during theprocedure and in some implementations, the fluid can be automaticallyremoved (e.g., via the fluid outlet). Substance concentration can becontrolled or varied during procedure. One substance can be flushed outbefore introducing another substance, which may prevent unwantedchemical interactions. Embodiments in which the fluid platform is aclosed system allow the use of more corrosive substances that may not bebeneficial if spilled into the patient's oral environment. Substantiallycontinuous replenishing of substances can help chemical reactions occurand may reduce the requirement for high concentration of such chemicals.

In various embodiments, a controlled fluid platform can be configuredfor one or more of the following. The fluid platform can allow analysisof fluid leaving the tooth to determine when procedure is complete. Thefluid platform can prevent overheating of the tooth (if the pressurewave generator 64 or other components generate heat) by irrigating thetooth chamber 65 with fluid through the fluid inlet 71. The fluidplatform can reduce or prevent air (e.g., gas) from being introducedinto the tooth chamber 65, which may lower the effectiveness ofirrigation, pressure waves, or cavitation. A controlled fluid platformcan allow cleaning action/energy to be more effective during aprocedure, e.g. fewer losses through mechanisms such as splashing, whichremoves both fluid mass and fluid momentum from the tooth chamber (whichotherwise could provide circulation). The fluid platform can allow teethto be treated in any orientation in space (e.g. upper or lower teeth maybe treated while the patient reclines in a dental chair). The fluidplatform can allow macroscopic circulation within the tooth to, forexample, effectively remove tissue and debris from canals and canalspaces and/or effectively replenish new treatment solution.

C. Examples of Combinations of Pressure Wave Generators and FluidPlatforms

In various embodiments, systems and methods may utilize some or all ofthe features of the apparatus shown in FIGS. 2, 3A, 3B, and 3C invarious combinations. These embodiments may include additional ordifferent features as well. For example, FIG. 4A schematicallyillustrates an example system for cleaning a tooth using pressure waves67. The system comprises a fluid retainer 66, a pressure wave generator64, and a fluid inlet 71. In some embodiments, the pressure wavegenerator 64 may deliver fluid to the tooth chamber 65 (e.g., a liquidjet) in combination with the fluid delivered from the fluid inlet 71. Insome such embodiments, the fluid inlet 71 may deliver fluid from adifferent fluid source than is used to provide the fluid for the liquidjet. For example, the inlet 71 may deliver a tissue dissolving agent oran antiseptic or antibacterial solution, and the pressure wave generator64 may deliver a beam of distilled water.

In other implementations, the pressure wave generator 64 may not act asa source of fluid, e.g., the pressure wave generator 64 may comprise anoptical fiber delivering laser light energy to the tooth chamber 65 or amechanical paddle or rotor. In such implementations, the fluid inlet 71can be used to deliver fluid to the tooth chamber 65 so as to provide afluid propagation medium for acoustic waves 67 generated by the pressurewave generator 64. Although the example system of FIG. 4A is shown ashaving a single fluid inlet 71 and a single pressure wave generator 64,this is for illustrative purposes, and in other embodiments, multiplefluid inlets 71 and/or pressure wave generators 64 can be used. Forexample, an optical fiber delivering light energy could be used inconjunction with a mechanical stirrer to provide pressure waves 67 andcirculation in the fluid chamber 63. In another example, the opticalfiber could be used with a liquid jet device.

The distal end of the pressure wave generator 64 may be submerged influid in the tooth chamber during at least a portion of the endodonticprocedure. For example, the distal end of the pressure wave generator 64may be disposed in the tooth chamber 65 while there is little or notliquid in the tooth chamber. Fluid can be added to the tooth chamber viathe fluid inlet 71 such that a fluid level rises above the distal end ofthe generator 64. The pressure wave generator 64 may then be activatedfor at least a portion of the endodontic procedure. During otherportions of the procedure, the pressure wave generator 64 may beinactive and/or disposed above the fluid level in the tooth chamber 65.

FIG. 4B schematically illustrates another example system for cleaning atooth 10 using pressure waves 67. In this example, the system includesthe fluid retainer 66, the pressure wave generator 64, and the fluidoutlet 72, which includes two vents 73. The use of multiple vents 73 maybe advantageous in cases where one of the vents 73 becomes blocked.Also, the dental practitioner may apply a suction tube to one of thevents to assist removal of fluid from the tooth chamber 65, while theother vent(s) remain available to inhibit under-pressurization oroverpressurization of the tooth chamber 65.

In the example shown in FIG. 4B, a tooth seal 75 is applied to aperimeter of a crown 12 of the tooth 10. As will be further describedherein, the tooth seal 75 may be formed from a substantially pliable orsemi-flexible material that sets in a relatively short time by itself orwith curing. The upper surface of the tooth seal 75 can be madesubstantially flat after application and removal of a flat plate to theupper surface (see, e.g., FIGS. 13B-14B). The upper surface of the toothseal 75 advantageously may provide a substantially flat working surfaceupon which the cap 70 of the fluid retainer 66 may be disposed orattached so that fluid in the tooth chamber 65 is inhibited from leakingout. FIG. 4B also shows an (optional) elastomeric material disposedunder the cap 70, which can help increase the water-tight seal betweenthe cap 70 and the tooth seal 75.

FIG. 4C shows another example system for cleaning a tooth 10 using apressure wave generator 64. In this example, the pressure wave generator64 comprises a liquid jet device having a guide tube 100 with a distalend that extends into the pulp cavity 26 of the tooth 10. In thisexample, the guide tube 100 comprises a channel or lumen 84 along whichthe liquid jet 60 can propagate until the jet 60 strikes an impingementplate 110 at the distal end. The impact of the jet 60 on the impingementplate 110 creates a spray of liquid that can exit one or more openingsat the distal end of the guide tube 100. A surface of the impingementplate 110 may reverberate due to the impact of the jet. The distal endof the guide tube 100 (including the openings) can be submerged belowthe surface of fluid retained in the tooth 10 by the fluid retainer 66.The impact of the jet 60 on the impingement surface 110 and/or theinteraction of the jet or spray with the fluid in the tooth chamber 65can create pressure waves 67 that may at least partially lead toeffective tooth cleaning as described herein. In this example, thedistal end of the guide tube 100 functions as a fluid inlet 71 todeliver the jet liquid to the tooth chamber 65 and as a pressure wavegenerator 64. This example system also includes a fluid outlet 72 withvents 73 to remove fluid from the tooth chamber 65 and to limitunder-pressurization or overpressurization of the tooth chamber 65.

FIG. 4D shows another example system for cleaning a tooth 10 using apressure wave generator 64. In this example, the system includes ahandpiece 50 with a distal end 58 that can be applied or attached to atooth seal 75 formed on the tooth 10. The distal end 58 includes thefluid retainer 66 (e.g., the cap 70). The handpiece 50 includes thefluid inlet 71, the fluid outlet 72, and the pressure wave generator 64.Portions of the fluid inlet 71 and the pressure wave generator 64 extendbeyond the cap 70 so that they can be disposed in the pulp chamber 28.

The handpiece 50 shown in FIG. 4D also includes vents 73 that are influid communication with the fluid outlet 72. The vents 73 permitambient air to be drawn into the fluid outlet 72 and to be entrainedwith fluid removed from the tooth 10. The vents 73 may help prevent thetooth chamber 65 from being depressurized (e.g., in the event that mostof the fluid is withdrawn from the tooth chamber 65), because as thepressure in the tooth chamber 65 decreases, air can be drawn in from thevents 73 rather than from the tooth chamber 65. The vents 73 may alsohelp prevent the tooth chamber 65 from being over-pressurized (e.g., inthe event that the fluid outlet 72 ceases to remove fluid), because asthe fluid pressure in the tooth increases, fluid can flow out of thevents 73 rather than being retained in the tooth chamber 65. The size,shape, and/or configuration of the vents 73 and/or their locations withrespect to the tooth chamber and/or the fluid outlet line 72 can beselected so that air is inhibited from entering the vents 73 and passingto the tooth chamber 65, where such air may decrease the effectivenessof acoustic cavitation. Further details regarding vents will be providedwith reference to FIGS. 12A and 12B. One, two, three, four, or morevents may be used in various embodiments.

FIGS. 2-4D are intended to illustrate various example systems andcombinations of components and features that can be used in variousimplementations for endodontic treatment. The example systemsillustrated in FIGS. 2-4D are not intended to limit the scope of thedisclosure. All possible variations and combinations of the componentsshown and described with respect to FIGS. 2-4D (and the other figures tobe described below) are contemplated.

(i) Additional Features of Some Fluid Platforms and Pressure WaveGenerators

Some dental procedures require instrumentation (e.g., endodontic files)to be inserted in the canals, which may not be desirable. For example,instrumentation may create a smear layer in the canal or force organicmatter out the apex 32 of the tooth 10, and instrumentation may weakenthe tooth. Also, for some teeth, not all portions of the root canalspaces can be instrumented because of canal curvature or complex canalgeometries, thus inhibiting instrumentation from being introduced intosome canals or from reaching the apex of the canal. Instrumentationgoing inside the canals may increase the chance of extrusion offluid/debris through the apex. Thus, as described herein, embodiments ofthe fluid platform can allow pressure waves 67 to be generated in fluidretained in the pulp cavity 26. The pressure waves 67 may be used toclean the tooth without instrumentation in some treatments. In someembodiments, the methods and systems described herein can be used withinstrumented methods. For example, endodontic files can be used toenlarge, shape, or clean root canals, and then a fluid platform may beapplied to the tooth and used to circulate a treatment fluid (e.g.,sodium hypochlorite solution) through the tooth chamber 65. A pressurewave generator 64 may be used to provide additional cleaning in thetooth chamber 65. Many variations and combinations of possibletechniques are contemplated that can be used by a dental practitioner.

Embodiments of the disclosed apparatus and method may allow removal ofcalcified structures (such as, but not limited to, pulp stones,calcified tissue covering the canal orifices, etc), which may limit orprevent access to and visualization of canals. Clearing such calcifiedstructures in the pulp chamber 28 can allow the system to find entrancesto canals automatically. For example, an undetected Mesiobuccal 2 (MB2)canal may appear by itself in some treatment methods. Embodiments ofsystems that create pressure waves only in the canals (and not in thepulp chamber) may require that canals be found or even enlarged inadvance.

In some embodiments, the pressure waves 67 generated in the pulp chamber28 can also remove calcified tissues and structures (e.g., pulp stones,tertiary dentin, etc.) inside the root canals. In some embodiments, thepressure waves 67 generated in the pulp chamber 28 can be used to removesmear layer and debris in instrumented canals. In some embodiments, thepressure waves 67 generated can reach all or substantially all interiorspaces of the tooth, e.g., substantially everything in contact with thefluid, including accessory canals, tubules, etc. In some embodiments,the pressure waves 67 can clean the pulp chamber and all canalssimultaneously, without requiring entering the root canals. In sometreatments, there is no need to find or locate the canals prior to theprocedure. The pressure wave cleaning may be able to reach the apex 32of the tooth and reach farther into canal spaces and tubules than othertreatment methods (e.g., with endodontic files or an ultrasonic tip).Embodiments of the fluid platform can allow pressure waves 67 to becreated in canals or to reach the canals via propagation through thefluid in the pulp cavity. Small probes can allow embodiments of thefluid platform to clean small canals, e.g., if the probes can beinserted into the canals. However, in some implementations, this mayrequire the operator to find the canals prior to the procedure.

D. Examples of Treatment Fluids

The treatment fluid used in any of the systems and methods describedherein may include sterile or distilled water, a medical-grade salinesolution, an antiseptic, an antibiotic, a decalcifying solution oragent, a tissue-dissolving solution or agent, etc. The treatment fluidmay include chemicals, medications, salts, anesthetics, bleaches,detergents, surfactants, irrigants, growth promoters, or any combinationthereof. The fluid may include a disinfectant, an oxidizingsolution/agent (e.g., hydrogen peroxide), a debriding solution/agent, achelating solution/agent, a bactericide, a deodorant, and/or a tissuesolvent. The treatment fluid can include endodontic solutions, solutes,or agents such as, e.g., sodium hypochlorite (NaOCl),ethylenediaminetetraacetic acid (EDTA), anolyte, chlorhexidine, calciumhydroxide, calcium hypochlorite, citric acid, boric acid, Dakin'ssolution, propylene glycol alginate (PGA), etc. The fluid may be acidic,neutral, or basic, and in some cases, the pH of the solution may beadjusted to provide a desired cleaning effect. The fluid may be changedduring treatment, for example, by changing the fluid reservoir or sourcethat supplies fluid to the fluid inlet or the liquid jet device (ifused). In some treatments, a fluid comprising a tissue dissolver can beused during a cleaning phase of the treatment, and an irrigant can beused to flush the cleaned pulp tooth chamber. Combinations of theforegoing (or other) fluids can be used, for example, mixtures ofsolutions or a sequence of different applied solutions. The type(s)and/or concentration(s) of chemical(s) in the fluid can change duringtreatment. One example of a treatment solution is water or saline withabout 0.3% to about 6% NaOCl.

In some cases, the treatment fluid may include small particles,abrasives, or biologically-active particles (e.g., biopowders), etc. Thefluid may include nanoparticles (e.g., nanorods or nanoshells). Forexample, in some systems where the pressure wave generator comprises alaser device, the light energy delivered from the laser may excite thenanoparticles and lead to more efficient photo-induced cavitation orpressure wave generation.

As will be described below, the treatment fluid (and/or any of solutionsadded to the treatment fluid) can be degassed compared to normal liquidsused in dental offices. For example, degassed distilled water may beused (with or without the addition of chemical agents or solutes).

(1) Examples of Possible Effects of Dissolved Gases in the TreatmentFluid

In some procedures, the fluid may include dissolved gases (e.g., air).For example, the fluids used in dental offices generally have a normaldissolved gas content (e.g., determined from the temperature andpressure of the fluid based on Henry's law). FIGS. 5A and 5Bschematically illustrate examples of procedures in with a pressure wavegenerator 64 (FIG. 5A) and a fluid inlet 71 (FIG. 5B) operate with or ina fluid environment that contains a fluid with dissolved gases. Theacoustic field of the pressure wave generator 64 and/or the flow orcirculation of fluids in the tooth chamber 65 can cause some of thedissolved gas to come out of solution and form bubbles 96 asschematically illustrated in FIGS. 5A and 5B.

The bubbles 96 can block small passageways in the tooth 10 (e.g., smallroot canal spaces 30 or dentinal tubules) and such blockages can act asif there were a “vapor lock” in the small passageways. In some suchprocedures, the presence of bubbles 96 may at least partially block,impede, or redirect propagation of acoustic waves 67 past the bubbles 96and may at least partially inhibit or prevent cleaning action fromreaching, for example, the apical regions of the root canal (see, e.g.,FIG. 5A). The bubbles 96 may block fluid flow or circulation fromreaching the apical regions or tubules, which may prevent or inhibit atreatment solution from reaching these areas of the tooth 10 (see, e.g.,FIG. 5B).

In certain endodontic procedures, cavitation is believed to play a rolein cleaning the tooth. Without wishing to be bound by any particulartheory, the physical process of cavitation inception may be, in someways, similar to boiling. One possible difference between cavitation andboiling is the thermodynamic paths that precede the formation of thevapor in the fluid. Boiling can occur when the local vapor pressure ofthe liquid rises above the local ambient pressure in the liquid, andsufficient energy is present to cause the phase change from liquid to agas. It is believed that cavitation inception can occur when the localambient pressure in the liquid decreases sufficiently below thesaturated vapor pressure, which has a value given in part by the tensilestrength of the liquid at the local temperature. Therefore, it isbelieved, although not required, that cavitation inception is notdetermined by the vapor pressure, but instead by the pressure of thelargest nuclei, or by the difference between the vapor pressure and thepressure of the largest nuclei. As such, it is believed that subjectinga fluid to a pressure slightly lower than the vapor pressure generallydoes not cause cavitation inception. However, the solubility of a gas ina liquid is proportional to pressure; therefore lowering the pressuremay tend to cause some of the dissolved gas inside the fluid to bereleased in the form of gas bubbles that are relatively large comparedto the size of bubbles formed at cavitation inception. These relativelylarge gas bubbles may be misinterpreted as being vapor cavitationbubbles, and their presence in a fluid may have been mistakenlydescribed in certain reports in the literature as being caused bycavitation, when cavitation may not have been present.

In the last stage of collapse of vapor cavitation bubbles, the velocityof the bubble wall may even exceed the speed of sound and create strongshock waves inside the fluid. The vapor cavitation bubble may alsocontain some amount of gas, which may act as a buffer and slow down therate of collapse and reduce the intensity of the shockwaves. Therefore,in certain endodontic procedures that utilize cavitation bubbles fortooth cleaning, it may be advantageous to reduce the amount of thedissolved air in the fluid to prevent such losses.

The presence of bubbles 96 that have come out of solution from thetreatment fluid may lead to other disadvantages during certainendodontic procedures. For example, if the pressure wave generator 64produces cavitation, the agitation (e.g. pressure drop) used to inducethe cavitation may cause the release of the dissolved air content beforethe water molecules have a chance to form a cavitation bubble. Thealready-formed gas bubble 96 may act as a nucleation site for the watermolecules during the phase change (which was intended to form acavitation bubble). When the agitation is over, the cavitation bubble isexpected to collapse and create pressure waves 67. However, cavitationbubble collapse might happen with reduced efficiency, because thegas-filled bubble may not collapse and may instead remain as a bubble.Thus, the presence of gas in the treatment fluid may reduce theeffectiveness of the cavitation process as many of the cavitationbubbles may be wasted by merging with gas-filled bubbles. Additionally,bubbles 96 in the fluid may act as a cushion to damp pressure waves 67propagating in the region of the fluid comprising the bubbles 96, whichmay disrupt effective propagation of the pressure waves 67 past thebubbles 96. Some bubbles 96 may either form inside the root canals 30 orbe transferred there by the flow or circulation of fluid in the tooth.Once inside the canals 30, the bubbles 96 may be hard to remove due torelatively high surface tension forces. This may result in blocking thetransfer of chemicals and/or pressure waves into the canals andtherefore may disrupt or reduce the efficacy of the treatment.

(2) Examples of Degassed Treatment Fluids

Accordingly, it may be advantageous in some systems and methods to use adegassed fluid, which may inhibit, reduce, or prevent bubbles 96 fromcoming out of solution during treatments as compared to systems andmethods that use normal (e.g., non-degassed) fluids. FIGS. 5C and 5Dschematically illustrate examples of dental procedures in which thetreatment fluid has a reduced gas content (compared with the normalfluids in the examples of FIGS. 5A and 5B) such that the root canals 30of the tooth 10 are substantially free of bubbles 96 that have come outof solution. As schematically illustrated in FIGS. 5C and 5D, acousticwaves 67 generated by the pressure wave generator 64 can propagatethrough the degassed fluid to reach and clean the apical regions 32 ofthe tooth 10 (FIG. 5C) and the degassed fluid from a fluid inlet 71 canreach the small root canal passages near the apex 32 of the tooth 10(FIG. 5D). The degassed fluid may also be able to flow or penetratedentinal tubules and clean matter from these hard to reach spaces. Insome procedures, the degassed fluid may be able to penetrate spaces assmall as about 500 microns, 200 microns, 100 microns, 10 microns, 5microns, 1 micron, or smaller, because the degassed fluid issufficiently gas-free that bubbles are inhibited from coming out ofsolution and blocking these spaces (as compared to use of fluids withnormal dissolved gas content).

For example, in some systems and methods, the degassed fluid can have adissolved gas content that is reduced when compared to the “normal” gascontent of water. For example, according to Henry's law, the “normal”amount of dissolved air in water (at 25 C and 1 atmosphere) is about 23mg/L, which includes about 9 mg/L of dissolved oxygen and about 14 mg/Lof dissolved nitrogen. In some embodiments, the degassed fluid has adissolved gas content that is reduced to approximately 10%-40% of its“normal” amount as delivered from a source of fluid (e.g., beforedegassing). In other embodiments, the dissolved gas content of thedegassed fluid may be reduced to approximately 5%-50% or 1%-70% of thenormal gas content of the fluid. In some treatments, the dissolved gascontent may be less than about 70%, less than about 50%, less than about40%, less than about 30%, less than about 20%, less than about 10%, lessthan about 5%, or less than about 1% of the normal gas amount.

In some embodiments, the amount of dissolved gas in the degassed fluidcan be measured in terms of the amount of dissolved oxygen (rather thanthe amount of dissolved air), because the amount of dissolved oxygen maybe more readily measured (e.g., via titration or optical orelectrochemical sensors) than the amount of dissolved air in the fluid.Thus, a measurement of dissolved oxygen in the fluid may serve as aproxy for the amount of dissolved air in the fluid. In some suchembodiments, the amount of dissolved oxygen in the degassed fluid can bein a range from about 1 mg/L to about 3 mg/L, in a range from about 0.5mg/L to about 7 mg/L, or some other range. The amount of dissolvedoxygen in the degassed fluid may be less than about 7 mg/L, less thanabout 6 mg/L, less than about 5 mg/L, less than about 4 mg/L, less thanabout 3 mg/L, less than about 2 mg/L, or less than about 1 mg/L.

In some embodiments, the amount of dissolved gas in the degassed fluidcan be in a range from about 2 mg/L to about 20 mg/L, in a range fromabout 1 mg/L to about 12 mg/L, or some other range. The amount ofdissolved gas in the degassed fluid may be less than about 20 mg/L, lessthan about 18 mg/L, less than about 15 mg/L, less than about 12 mg/L,less than about 10 mg/L, less than about 8 mg/L, less than about 6 mg/L,less than about 4 mg/L, or less than about 2 mg/L.

In other embodiments, the amount of dissolved gas may be measured interms of air or oxygen percentage per unit volume. For example, theamount of dissolved oxygen (or dissolved air) may be less than about 5%by volume, less than about 1% by volume, less than about 0.5% by volume,or less than about 0.1% by volume.

The amount of dissolved gas in a liquid may be measured in terms of aphysical property such as, e.g., fluid viscosity or surface tension. Forexample, degassing water tends to increase its surface tension. Thesurface tension of non-degassed water is about 72 mN/m at 20° C. In someembodiments, the surface tension of degassed water can be about 1%, 5%,or 10% greater than non-degassed water.

In some treatment methods, one or more secondary fluids may be added toa primary degassed fluid (e.g., an antiseptic solution can be added todegassed distilled water) (see, e.g., FIG. 6B). In some such methods,the secondary solution(s) may be degassed before being added to theprimary degassed fluid. In other applications, the primary degassedfluid can be sufficiently degassed such that inclusion of the secondaryfluids (which may have normal dissolved gas content) does not increasethe gas content of the combined fluids above what is desired for aparticular dental treatment.

In various implementations, the treatment fluid may be provided asdegassed liquid inside sealed bags or containers. The fluid may bedegassed in a separate setup in the operatory before being added to afluid reservoir. In an example of an “in-line” implementation, the fluidcan be degassed as it flows through the system, for example, by passingthe fluid through a degassing unit attached along a fluid line (e.g.,the fluid inlet 71). Examples of degassing units that can be used invarious embodiments include: a Liqui-Cel® MiniModule® Membrane Contactor(e.g., models 1.7×5.5 or 1.7×8.75) available from Membrana-Charlotte(Charlotte, N.C.); a PermSelect® silicone membrane module (e.g., modelPDMSXA-2500) available from MedArray, Inc. (Ann Arbor, Mich.); and aFiberFlo® hollow fiber cartridge filter (0.03 micron absolute) availablefrom Mar Cor Purification (Skippack, Pa.). The degassing may be doneusing any of the following degassing techniques or combinations ofthereof: heating, helium sparging, vacuum degassing, filtering,freeze-pump-thawing, and sonication.

In some embodiments, degassing the fluid can include de-bubbling thefluid to remove any small gas bubbles that form or may be present in thefluid. De-bubbling can be provided by filtering the fluid. In someembodiments, the fluid may not be degassed (e.g., removing gas dissolvedat the molecular level), but may be passed through a de-bubbler toremove the small gas bubbles from the fluid.

In some embodiments, the degassing system 41 can include a dissolved gassensor to determine whether the treatment fluid is sufficiently degassedfor a particular endodontic treatment. A dissolved gas sensor can bedisposed downstream of the mixing system 43 and used to determinewhether mixing of solutes has increased the dissolved gas content of thetreatment fluid after addition of solutes, if any. The solute source 42may include a dissolved gas sensor For example, a dissolved gas sensormay measure the amount of dissolved oxygen in the fluid as a proxy forthe total amount of dissolved gas in the fluid, since dissolved oxygenmay be measured more readily than dissolved gas (e.g., nitrogen orhelium). Dissolved gas content can be inferred from dissolved oxygencontent based at least partly on the ratio of oxygen to total gas in air(e.g., oxygen is about 21% of air by volume). Dissolved gas sensors caninclude electrochemical sensors, optical sensors, or sensors thatperform a dissolved gas analysis. Examples of dissolved gas sensors thatcan be used with embodiments of various systems disclosed herein includea Pro-Oceanus GTD-Pro or HGTD dissolved gas sensor available fromPro-Oceanus Systems Inc. (Nova Scotia, Canada) and a D-Opto dissolvedoxygen sensor available from Zebra-Tech Ltd. (Nelson, New Zealand). Insome implementations, a sample of the treatment can be obtained andgases in the sample can be extracted using a vacuum unit. The extractedgases can be analyzed using a gas chromatograph to determine dissolvedgas content of the fluid (and composition of the gases in some cases).

Accordingly, in the example systems shown in FIGS. 2-4C (and the examplesystems shown and described below), the fluid delivered to the toothfrom a fluid inlet and/or the fluid used to generate the jet in a liquidjet device may comprise a degassed fluid that has a dissolved gascontent less than normal fluid. The degassed fluid may be used, forexample, to generate the high-velocity liquid beam for generatingpressure waves, to substantially fill or irrigate a chamber in the tooth(e.g., the pulp cavity and/or canal spaces), to provide a propagationmedium for acoustic waves, to inhibit formation of air (or gas) bubblesin the tooth chamber (e.g., in canal spaces or tubules), and/or toprovide flow of the degassed fluid into small spaces in the tooth (e.g.,small canals, tubules, etc.). In embodiments utilizing a liquid jet, useof a degassed fluid may inhibit bubbles from forming in the jet due tothe pressure drop at a nozzle orifice where the liquid jet is formed.

Thus, examples of methods for endodontic treatment comprise flowing adegassed fluid onto a tooth or tooth surface or into a tooth chamber.The degassed fluid may comprise a tissue dissolving agent and/or adecalcifying agent. The degassed fluid may have a dissolved oxygencontent less than about 9 mg/L, less than about 7 mg/L, less than about5 mg/L, less than about 3 mg/L, less than about 1 mg/L, or some othervalue. A fluid for endodontic treatment may comprise a degassed fluidwith a dissolved oxygen content less than about 9 mg/L, less than about7 mg/L, less than about 5 mg/L, less than about 3 mg/L, less than about1 mg/L, or some other value. The fluid may comprise a tissue dissolvingagent and/or a decalcifying agent. For example, the degassed fluid maycomprise an aqueous solution of less than about 6% by volume of a tissuedissolving agent and/or less than about 20% by volume of a decalcifyingagent.

II. Example Embodiments of Apparatus and Methods for Dental Treatments

A. Examples of Pressure Wave Generators

1. Examples of Liquid Jet Apparatus

(i) Example Systems for Generating a High-Velocity Jet

FIG. 6A is a block diagram that schematically illustrates an embodimentof a system 38 adapted to generate a high-velocity jet 60 of fluid foruse in dental procedures. The system 38 comprises a motor 40, a fluidsource 44, a pump 46, a pressure sensor 48, a controller 51, a userinterface 53, and a handpiece 50 that can be operated by a dentalpractitioner to direct the jet 60 toward desired locations in apatient's mouth. The pump 46 can pressurize fluid received from thefluid source 44. The pump 46 may comprise a piston pump in which thepiston is actuatable by the motor 40. The high-pressure liquid from thepump 46 can be fed to the pressure sensor 48 and then to the handpiece50, for example, by a length of high-pressure tubing 49. The pressuresensor 48 may be used to sense the pressure of the liquid andcommunicate pressure information to the controller 51. The controller 51can use the pressure information to make adjustments to the motor 40and/or the pump 46 to provide a target pressure for the fluid deliveredto the handpiece 50. For example, in embodiments in which the pump 46comprises a piston pump, the controller 51 may signal the motor 40 todrive the piston more rapidly or more slowly, depending on the pressureinformation from the pressure sensor 48. In some embodiments, thepressure of the liquid that can be delivered to the handpiece 50 can beadjusted within a range from about 500 psi to about 50,000 psi (1 psi is1 pound per square inch and is about 6895 Pascal (Pa)). In certainembodiments, it has been found that a pressure range from about 2,000psi to about 15,000 psi produces jets that are particularly effectivefor endodontic treatments. In some embodiments, the pressure is about10,000 psi.

The fluid source 44 may comprise a fluid container (e.g., an intravenousbag) holding any of the treatments fluids described herein. Thetreatment fluid may be degassed, with a dissolved gas content less thannormal (e.g., non-degassed) fluids. Examples of treatment fluids includesterile water, a medical-grade saline solution, an antiseptic orantibiotic solution (e.g., sodium hypochlorite), a solution withchemicals or medications, or any combination thereof. More than onefluid source may be used. In certain embodiments, it is advantageous forjet formation if the liquid provided by the fluid source 44 issubstantially free of dissolved gases, which may reduce theeffectiveness of the jet and the pressure wave generation. Therefore, insome embodiments, the fluid source 44 comprises degassed liquid such as,e.g., degassed distilled water. A bubble detector (not shown) may bedisposed between the fluid source 44 and the pump 46 to detect bubblesin the liquid and/or to determine whether liquid flow from the fluidsource 44 has been interrupted or the container has emptied. Also, asdiscussed above degassed fluids may be used. The bubble detector can beused to determine whether small air bubbles are present in the fluidthat might negatively impact jet formation or acoustic wave propagation.Thus in some embodiments, a filter or de-bubbler (not shown) can be usedto remove small air bubbles from the liquid. The liquid in the fluidsource 44 may be at room temperature or may be heated and/or cooled to adifferent temperature. For example, in some embodiments, the liquid inthe fluid source 44 can be chilled to reduce the temperature of the highvelocity jet 60 generated by the system 38, which may reduce or controlthe temperature of the fluid inside a tooth 10. In some treatmentmethods, the liquid in the fluid source 44 can be heated, which mayincrease the rate of chemical reactions that may occur in the tooth 10during treatment.

The handpiece 50 can be configured to receive the high pressure liquidand can be adapted at a distal end to generate a high-velocity beam orjet 60 of liquid for use in dental procedures. In some embodiments, thesystem 38 may produce a coherent, collimated jet of liquid. Thehandpiece 50 may be sized and shaped to be maneuverable in the mouth ofa patient so that the jet 60 may be directed toward or away from variousportions of the tooth 10. In some embodiments, the handpiece 50comprises a housing or cap that can be coupled to the tooth 10.

The controller 51 may comprise a microprocessor, a special or generalpurpose computer, a floating point gate array, and/or a programmablelogic device. The controller 51 may be used to control safety of thesystem 38, for example, by limiting system pressures to be below safetythresholds and/or by limiting the time that the jet 60 is permitted toflow from the handpiece 50. The system 38 may also include a userinterface 53 that outputs relevant system data or accepts user input(e.g., a target pressure). In some embodiments, the user interface 53comprises a touch screen graphics display. In some embodiments, the userinterface 53 may include controls for a dental practitioner to operatethe liquid jet apparatus. For example, the controls can include a footswitch to actuate or deactuate the jet.

The system 38 may include additional and/or different components and maybe configured differently than shown in FIG. 6A. For example, the system38 may include an aspiration pump that is coupled to the handpiece 50(or an aspiration cannula) to permit aspiration of organic matter fromthe mouth or tooth 10. In other embodiments, the system 38 may compriseother pneumatic and/or hydraulic systems adapted to generate thehigh-velocity beam or jet 60.

(ii) Example Systems for Providing a Fluid Platform

FIG. 6B is a block diagram that schematically illustrates an embodimentof a system 38 for providing fluid to a fluid platform 61 that is influid communication with a tooth 10. Some of the components in thissystem 38 can be generally similar to those described with respect tothe system 38 shown in FIG. 6A. The system 38 includes a solvent source39 (which may be the same or different from the fluid source 44 shown inFIG. 6A). The solvent may comprise water. The solvent flows to adegassing system 41 where it can be degassed to a desired level. Thesystem 38 can include a mixing system 43 configured to mix solute(s)from a solutes source 42 into the fluid. The solute(s) can include anysolid, liquid, or gas substances that may be added to the solvent. Forexample, the solute(s) can include antiseptic or antibacterial fluids orcompounds (e.g., NaOCl or EDTA), surfactants, medicaments,nanoparticles, etc. Liquid solute(s) may, but need not be, degassed. Thesolvent and solutes flow to the fluid platform 61 via the tubing 49. Thefluid platform 61 can include any of the example fluid platforms orother components described herein. For example, the fluid platform 61can include a pressure wave generator to generate acoustic waves in thetooth to provide tooth cleaning.

In the illustrated system 38, the tubing 49 can be fluidly attached to afluid inflow to the fluid platform 61. In some embodiments the flow rateof the treatment fluid (e.g., solvent plus solute(s)) in the fluidinflow can be in the range of about 0.4-1.2 cc/s. In other embodiments,the flow rate range can be about 0.2 to 2 cc/s, 0.01 to 5 cc/s, or othervalues (e.g., up to about 10, 20, or 50 cc/s). In one embodiment, theinflux of the fluid can be pulsating. In other embodiments, the influxof the fluid can be intermittent. In one embodiment, the influx of thefluid can be substantially uniform over time.

In the illustrated system 38, the fluid platform 61 can include a fluidoutlet that can remove fluid from the tooth. At least a portion of thisfluid may be passed to a monitoring system 45, which can monitor thefluid flowing from the tooth to determine the extent or progress of thetreatment. For example, the monitoring system 45 can include one or moremonitoring sensors 74 that may be generally similar to the monitoringsensors described with reference to FIG. 3C. The monitoring system 45may monitor the extent or progress of tooth cleaning and may signal thedental practitioner, via the user interface 53, when the cleaning iscomplete. In some implementations, the controller 51 (or the monitoringsystem 45) may use feedback (e.g., based on properties monitored by themonitoring system) to regulate, adjust, or control components of thesystem during the treatment. Such use of feedback advantageously mayallow aspects of the endodontic treatment to be automated. For example,feedback can be used to activate or deactivate a pressure wave generatoror fluid source to more efficiently provide treatment to the patient.

A fluid outlet can be connected to a suction system 47, which may besimilar to suction or evacuation units found in dental offices. Forexample, some dental evacuation units are designed to operate at about−6 in-Hg to about −8 in-Hg and have an airflow rate of about 7 standardcubic feet per minute (SCFM) per chairside high-volume inlet.Independent vacuum systems can be used. In one embodiment, the operatingpressure of the evacuation unit is about −4 to −10 in-Hg. In otherembodiments, the operating pressure is in a range of about −0.1 to −5in-Hg or −5 to −10 in-Hg or −10 to −20 in-Hg, or other values. In someembodiments, the flow provided by the evacuation unit can be pulsating.In another embodiment, the evacuation unit flow can be intermittent. Inone embodiment, the evacuation unit flow can be substantially uniform.The air flow rate of the evacuation unit can be 5 to 9 SCFM or 2 to 13SCFM or 0.1 to 7 SCFM or 7 to 15 SCFM or 15 to 30 SCFM or 30 to 50 SCFM,or other values.

In some implementations, it may be desired that the fluid entering thefluid platform 61 be degassed to a certain degree (e.g., about 40% ofnormal dissolved gas amount in one example). In some suchimplementations, the degassing system 41 may “over-degas” the solvent sothat the solvent's dissolved gas content is below the desired degree(e.g., about 35% in this example) so that when solute(s) are added bythe mixing system 43, the resulting fluid (solvent plus solute) isdegassed to less than the desired degree (e.g., adding un-degassedantiseptic solution may raise the dissolved gas content to 38% in thisexample).

In the system 38 shown in FIG. 6B, the solute mixing system 43 isdownstream from the degassing system 41. Some solutes may be able tochemically degrade wet components of the degassing system 41 (e.g.,bleach can attack gaskets, filters, etc.). An advantage of thedownstream arrangement shown in FIG. 6B is that such solutes can beadded after the solvent has been degassed; therefore, these solutes willnot pass through (and possibly degrade) the degassing system 41.

In some implementations, heat dissipated by the pressure wave generator64 may accumulate and may cause a temperature increase in the fluid inthe tooth chamber 65 (and/or in the tooth). A sufficient temperatureincrease may be damaging to the oral tissues. A significant temperatureincrease may occur during some procedures utilizing certain embodimentsof uncontrolled fluid platforms. In some embodiment of the vented fluidplatform, the mean fluid temperature and the mean tooth temperature mayremain below temperatures safely tolerated by oral tissues. In someembodiments, the mean temperature remains between about 30 to 40° C. Inother embodiments, the mean temperature remains between about 20 to 50°C., 10 to 60° C., 5 to 70° C., or else. The temperature may fluctuateand vary throughout the pulp cavity during the treatment and thereforethe mean value of temperature may vary or fluctuate.

The temperature of the fluid inside the pulp cavity and the temperatureof the tooth can depend at least in part on factors including thetemperature of the treatment fluid supplied to the tooth, the heatdissipation rate of the pressure wave generator 64, the temperature ofthe fluid supply line (including the pump), and the flow rate of thetreatment fluid. One or more of these factors (or others) may beadjusted during treatment to maintain a desired temperature of the fluidin the tooth, the tooth itself, the fluid flowing from the pulp chamber,etc. In various embodiments, one or more temperature sensors (e.g.,thermistors) may be disposed in the handpiece, in or near the pressurewave generator 64, in the pulp cavity in the tooth, or in the fluidinflow and/or fluid outflow to the fluid platform, or elsewhere tomonitor temperatures during the treatment. The systems shown in FIGS. 6Aand 6B can include additional components (not shown) to regulate thetemperature of the fluid anywhere along the fluid paths illustrated.

The system 38 may include additional and/or different components and maybe configured differently than shown in FIG. 6B. For example, the mixingsystem 43 and the degassing system 41 can be combined. Either or both ofthese systems can be disposed anywhere in the fluid flow path upstreamof the fluid platform 61. Also, other embodiments do not need to includeall the components shown in FIGS. 6A and 6B. For example, someembodiments do not include a degassing system, a mixing system, and/or amonitoring system. FIGS. 6A and 6B are intended to be illustrative ofthe type of fluid arrangements that are possible and are not intended tobe limiting.

Embodiments of the systems shown in FIGS. 6A and 6B may utilizecomponents described in or be configured similarly to embodiments of theapparatus and systems described in U.S. Pat. No. 6,224,378, issued May1, 2001, entitled “METHOD AND APPARATUS FOR DENTAL TREATMENT USING HIGHPRESSURE LIQUID JET,” U.S. Pat. No. 6,497,572, issued Dec. 24, 2002,entitled “APPARATUS FOR DENTAL TREATMENT USING HIGH PRESSURE LIQUIDJET,” U.S. Patent Publication No. 2007/0248932, published Oct. 25, 2007,entitled “APPARATUS AND METHODS FOR TREATING ROOT CANALS OF TEETH,” U.S.Patent Publication No. 2010/0143861, published Jun. 10, 2010, entitled“APPARATUS AND METHODS FOR MONITORING A TOOTH,” U.S. Patent PublicationNo. 2011/0111365, published May 12, 2011, entitled “APPARATUS ANDMETHODS FOR ROOT CANAL TREATMENTS,” and/or U.S. Patent Publication No.2011/0117517, published May 19, 2011, entitled “LIQUID JET APPARATUS ANDMETHODS FOR DENTAL TREATMENTS”; the entire disclosure of each of theforegoing patents and publications is hereby incorporated by referenceherein for all that it teaches or discloses.

(iii) Examples of a Coherent Collimated Jet

In certain embodiments, the system 38 may be configured to produce aliquid jet 60 that forms a substantially parallel beam (e.g., is“collimated”) over distances ranging from about 0.01 cm to about 10 cm.In some embodiments, the velocity profile transverse to the propagationaxis of the jet is substantially constant (e.g., is “coherent”). Forexample, in some implementations, away from narrow boundary layers nearthe outer surface of the jet 60 (if any), the jet velocity issubstantially constant across the width of the jet. Therefore, incertain advantageous embodiments, the liquid jet 60 delivered by thedental handpiece 50 may comprise a coherent, collimated jet (a “CCjet”). In some implementations, the CC jet may have velocities in arange from about 100 m/s to about 300 m/s, for example, about 190 m/s insome embodiments. In some implementations, the CC jet can have adiameter in a range from about 5 microns to about 1000 microns, in arange from about 10 microns to about 100 microns, in a range from about100 microns to about 500 microns, or in a range from about 500 micronsto about 1000 microns. Further details with respect to CC jets that canbe produced by embodiments of the system and apparatus described hereincan be found in U.S. Patent Publication No. 2007/0248932 and/or U.S.Patent Publication No. 2011/0117517, each of which is herebyincorporated by reference herein in its entirety for all that itdiscloses or teaches.

(iv) Examples of Handpieces

FIG. 7 is a side view schematically illustrating an embodiment of ahandpiece 50 comprising an embodiment of a positioning member configuredto deliver the liquid jet 60 to a portion of the tooth 10. In variousembodiments, the positioning member comprises a guide tube 100. Thehandpiece 50 comprises an elongated tubular barrel 52 having a proximalend 56 that is adapted to engage tubing 49 from the system 38 and adistal end 58 adapted to be coupled or attached to the tooth 10. Thebarrel 52 may include features or textures 55 that enhance grasping thehandpiece 50 with the fingers and thumb of the operator. The handpiece50 can be configured to be handheld. In some cases, the handpiece 50 canbe configured to be portable, movable, orientable, or maneuverable withrespect to the patient. In some implementations, the handpiece 50 can beconfigured to be coupled to a positioning device (e.g., a maneuverableor adjustable arm).

The distal end 58 of the handpiece 50 can comprise a housing or cap 70that can be coupled to the tooth 10 (see, e.g., FIG. 4D). The cap 70 maybe a detachable member that can be sized/shaped to fit on the patient'stooth and/or to position the distal end of the guide tube 100 at adesired location in the pulp cavity 26. A kit of caps may be providedsuch that a dental practitioner can select an appropriately-sized capand attach it to the handpiece 50 (see, e.g., description of toothsizing below).

The handpiece 50 may include a fluid inlet 71 for delivering treatmentfluid to the tooth chamber 65, a fluid outlet 72 for removing fluid fromthe tooth (e.g., waste fluid), a pressure wave generator 64, a powerline (e.g., to provide energy to a pressure wave generator), or acombination of some or all of the foregoing. The handpiece 50 mayinclude other components such as, e.g., an irrigation line to irrigatethe tooth area, a light source to illuminate the tooth area, etc. Insome cases, the pressure wave generator 64 (e.g., a liquid jet)comprises the fluid inlet 71 (e.g., the jet). The handpiece 50 can beused to apply the pressure wave generator 64 relative to the tooth 10.The handpiece 50 can be applied to the tooth 10 so as to create asubstantially closed fluid circuit as the distal end 58 of the handpiece50 engages the tooth 10, thereby enabling fluid to be delivered into andout of the tooth chamber 65 without substantial spillage or leakage intothe patient's mouth. As described herein, the handpiece 50 may include afluid retention member (e.g., sponge or vent) to reduce the likelihoodof fluid leakage and/or to allow fluid to flow from the tooth chamber 65(e.g., to inhibit overpressurization or under-pressurization). The fluidretention member can be configured to inhibit air from entering thetooth chamber 65 (which may reduce the effectiveness of cavitation)while permitting air to enter a fluid outlet 72 (e.g., suction line).

The handpiece 50 can be shaped or sized differently than shown in FIG.7. For example, the elongated tubular barrel 52 may not be used, and adental practitioner may maneuver the cap 70 into a desired location inthe patient's mouth. The patient may bite down on the cap 70 to hold thecap 70 in place during a treatment (see, e.g., FIG. 11). In otherembodiments, the handpiece 50 can include a device that is clamped orattached to the tooth 10 (e.g., via a rubber dam clamp commonly used inendodontic procedures) such that the device doesn't require substantialuser intervention during the procedure (see, e.g., FIGS. 10A and 10B).

The handpiece 50 can be disposable (e.g., single-use) or reusable. Inone embodiment, the handpiece 50 is disposable, but the pressure wavegenerator 64 is reusable. In another embodiment, the handpiece 50 isreusable, and certain components of the pressure wave generator 64(e.g., a guide tube) are disposable. In some embodiments, the distal end58 of the handpiece 50 can include additional components such as, forexample, a sealer or gasket (which may be an elastomeric material or aclosed-cell foam), spacers (e.g., to position the distal end of theguide tube 100 at a desired location in the tooth chamber), vents, etc.

(v) Examples of Guide Tubes

FIG. 8 schematically illustrates a distal end 58 of an example handpiece50 comprising a guide tube 100. In this example, the fluid retainer(e.g., cap and/or flow restrictor) is disposed inside the distal end 58of the handpiece 50. Embodiments of the guide tube 100 can be sized orshaped such that a distal end 104 of the guide tube 100 can bepositioned through an endodontic access opening formed in the tooth 10,for example, on an occlusal surface, a buccal surface, or a lingualsurface. For example, the distal end 104 of the guide tube 100 may besized or shaped so that the distal end 104 can be positioned in the pulpcavity 26 of the tooth 10, e.g., near the pulpal floor, near openings tothe canal space 30, or inside the canal openings. The size of the distalend 104 of the guide tube 100 can be selected so that the distal end 104fits through the access opening of the tooth 10. In some embodiments,the width of the guide tube 100 can be approximately the width of aGates-Glidden drill, for example, a size 4 Gates-Glidden drill. In someembodiments, the guide tube 100 can be sized similarly to gauge 18, 19,20, or 21 hypodermic tubes. The width of the guide tube 100 may be in arange from about 0.1 mm to about 5 mm, in a range from about 0.5 mm toabout 2.0 mm, or some other range. The length of the guide tube 100 canbe selected so that the distal end 104 of the guide tube 100 can bedisposed at a desired location in the mouth. For example, the length ofthe guide tube 100 between a proximal end 102 and the distal end 104 maybe in a range from about 1 mm to about 50 mm, from about 10 mm to about25 mm, or in some other range. In some embodiments, the length can beabout 13 mm or about 18 mm, which may allow the distal end 104 of theguide tube 100 to reach the vicinity of the pulpal floor in a wide rangeof teeth. For teeth that may not have a pulpal chamber or a pulpal floor(e.g., anterior teeth), the distal end 104 of the guide tube 100 can beinserted into the canal space of the tooth 10. The guide tube 100 may beattached to the handpiece 50, or, in some cases, be a detachable orremovable member. The guide tube 100 may be single-use or disposable. Insome implementations, a kit of guide tubes is provided, and a dentalpractitioner can select a guide tube having a desired length (see, e.g.,description of tooth sizing below).

Certain embodiments of the guide tube 100 can comprise an impingementmember 110 (which also may be referred to herein as a deflector). Thejet 60 can propagate along the channel 84 and impinge upon a surface ofthe impingement member 110, whereby at least a portion of the jet 60 canbe slowed, disrupted or deflected, which can produce a spray 90 ofliquid. The spray 90 may comprise droplets, beads, mist, jets, or beamsof liquid in various implementations. Embodiments of the guide tube 100which include an impingement member 110 may reduce or prevent possibledamage that may be caused by the jet 60 during certain dentaltreatments. For example, use of the impingement member 110 may reducethe likelihood that the jet 60 may undesirably cut tissue or propagateinto the root canal spaces 30 (which may undesirably pressurize thecanal spaces in some cases). The design of the impingement member 110may also enable a degree of control over the fluid circulation ordynamic pressures that can occur in the pulp cavity 26 during treatment.

The impingement member 110 may be disposed in a chamber 63, 65 or cavityin the tooth 10. In some methods, the impingement member 110 is disposedin fluid in the tooth 10, and the liquid jet 60 impacts an impingementsurface of the impingement member 110 while the impingement member 110is disposed in the cavity. The liquid jet 60 may be generated in air orfluid, and in some cases, a portion of the liquid jet 60 passes throughat least some (and possibly a substantial portion) of fluid in thecavity in the tooth 10 before impacting the impingement member 110. Insome cases, the fluid in the tooth cavity 65 may be relatively static;in other cases, the fluid in the tooth cavity 65 may circulate, beturbulent, or have fluid velocities that are less than (or substantiallyless than) the speed of the high-velocity liquid jet.

In some implementations, the impingement member 110 is not used, and thejet 60 can exit the guide tube 100 without substantial interference fromportions of the guide tube 100. In some such implementations, afterexiting the guide tube 100, the jet 60 may be directed toward a dentinalsurface, where the jet 60 may impact or impinge upon the dentinalsurface to provide acoustic energy to the tooth 10, to superficiallyclean the tooth 10, and so forth.

The guide tube 100 can include an opening 120 that permits the spray 90to leave the distal end 104 of the guide tube 100. In some embodiments,multiple openings 120 can be used, for example, two, three, four, five,six, or more openings. The opening 120 can have a proximal end 106 and adistal end 108. The distal end 108 of the opening 120 can be disposednear the distal end 104 of the guide tube 100. The opening 120 canexpose the liquid jet 60 (and/or the spray 90) to the surroundingenvironment, which may include air, liquid, organic material, etc. Forexample, in some treatment methods, when the distal end 104 of the guidetube 100 is inserted into the pulp cavity 26, the opening 120 permitsthe material or fluid inside the pulp cavity 26 to interact with the jet60 or spray 90. A hydroacoustic field (e.g., pressure waves, acousticenergy, etc.) may be established in the tooth 10 (e.g., in the pulpcavity 26, the canal spaces 30, etc.) by the impingement of the jet 60on the impingement member 110, interaction of the fluid or material inthe tooth 10 with the jet 60 or they spray 90, fluid circulation oragitation generated in the pulp cavity 26, or by a combination of thesefactors (or other factors). The hydroacoustic field may include acousticpower over a relatively broad range of acoustic frequencies (e.g., fromabout a few kHz to several hundred kHz or higher; see, e.g., FIG. 2B-1).The hydroacoustic field in the tooth may influence, cause, or increasethe strength of effects including, e.g., acoustic cavitation (e.g.,cavitation bubble formation and collapse, microjet formation), fluidagitation, fluid circulation, sonoporation, sonochemistry, and so forth.It is believed, although not required, that the hydroacoustic field,some or all of the foregoing effects, or a combination thereof may actto disrupt or detach organic or inorganic material in the tooth, whichmay effectively clean the pulp cavity 26 and/or the canal spaces 30.

The length of the opening 120 between the proximal end 106 and thedistal end 108 is referred to as X (see, e.g., FIG. 8). In variousembodiments, the length X may be in a range from about 0.1 mm toapproximately the overall length of the guide tube 100. In someembodiments, the length X is in a range from about 1 mm to about 10 mm.In some cases, the length X is selected so that the opening 120 remainssubmersed by fluid or material in the pulp cavity 26 of the tooth 10during treatment. A length X of about 3 mm can be used for a widevariety of teeth. In some embodiments, the length X is a fraction of theoverall length of the guide tube 100. The fraction can be about 0.1,about 0.25, about 0.5, about 0.75, about 0.9, or a different value. Insome embodiments, the length X is a multiple of the width of the guidetube 100 or the channel 84. The multiple can be about 0.5, about 1.0,about 2.0, about 4.0, about 8.0, or a different value. The multiple canbe in a range from about 0.5 to about 2.0, about 2.0 to about 4.0, about4.0 to about 8.0, or more. In other embodiments, the length X is amultiple of the width of the jet, e.g., 5 times, 10 times, 50 times, or100 times the width of the jet. The multiple can be in a range fromabout 5 to about 50, about 50 to about 200, about 200 to about 1000, ormore. In some implementations, the length X of the opening 120 can beselected (at least in part) such that the hydroacoustic field generatedin a tooth has desired properties including, e.g., desired acousticpower in the tooth at one or more acoustic frequencies. In someimplementations, the length of X is selected so that both the proximaland distal ends 106, 108 of the opening 120 remain submerged in fluidduring treatment.

Thus, the guide tube 100 can be used to deliver a pressure wavegenerator 64 to the tooth chamber 65. Embodiments of the guide tube 100may, but need not, be used with non-jet pressure wave generators. Forexample, in an optical arrangement, an optical fiber can be disposedalong the lumen or channel 84 of the guide tube 100. The fiber can havea tip configured to radiate light energy propagating in the fiber outinto the fluid in the tooth chamber 65. The tip may be disposed so thatthe radiating light energy can exit the tip through a window 120 in theguide tube 100. In other embodiments, the tip of the fiber may extendbeyond the distal end 104 of the guide tube 100 (e.g., the impingementmember 110 (described below) and the window 120 need not be used). In anacoustic arrangement, an ultrasonic tip or an ultrasonic paddle can bedisposed along the lumen or channel 84 of the guide tube 100. The guidetube 100 can protect the optical fiber or ultrasonic tip/transducer fromdamage when inserted into the tooth 10.

(vi) Examples of Flow Restrictors (e.g., Sponges, Vents, etc.)

As discussed herein, embodiments of flow restrictors may be used to helpretain fluid in the tooth chamber 65, to inhibit backflow or splashingof fluid from the tooth, to permit fluid to leave the tooth chamber 65to (e.g., to reduce the potential for over-pressurization of thechamber), to inhibit air from entering the tooth chamber 65 (which mayreduce the effectiveness of pressure waves), and/or to permit air to beentrained with fluid removed from the tooth chamber 65 (e.g., to reducethe potential for under-pressurization of the chamber). In variousembodiments, flow restrictors 68 can include sponges, vents, permeableor semi-permeable membranes, etc. that will be described with referenceto FIGS. 12A and 12B.

(1) Examples of Sponges

In some cases the flow restrictor 68 can comprise a sponge. Withreference to FIG. 12A, the sponge can be substantially cylindrical andcan substantially surround the guide tube 100. The sponge can be used inaddition to or as an alternative to a cap 70 that can be disposed towardthe distal end 58 of the handpiece 50. In some embodiments, the spongecan be disposed within the cap 70 (see, e.g., FIGS. 3B, 3C, 9, 10A, and11) to assist cushioning and positioning the cap 70 on the tooth 10 andto help prevent leakage between the cap 70 and the tooth 10 (or thetooth seal 75, if used). The sponge may be configured to contact aportion of the tooth 10 during the dental treatment. In some cases, thesponge is disposed loosely around the guide tube 100. The sponge may beremovably attached to the guide tube 100 in some cases. The sponge canbe configured to conform to the crown 12 of the tooth 10 undertreatment. The sponge can be configured such that jet or spray thatemerges from the opening 120 (or liquid from other sources such as,e.g., the flow tube) is sufficiently retained within the pulp cavity 26so that the distal end 104 of the guide tube 100 may be contained orsubmersed in the fluid. The sponge may be attached to the distal end 58of the handpiece 50 via an adhesive, clip, etc. The sponge may insteadbe attached directly to the tooth (or to the tooth seal 75, if used).

In certain treatment methods, the flow restrictor 68 may, but does notneed to, substantially seal the opening to a cavity in the tooth 10 suchthat the cavity is substantially water tight. For example, in certaintreatment methods, the flow restrictor 68 inhibits back flow (e.g.,splashback) of fluid out of the cavity but need not prevent all fluidoutflow from the tooth 10. For example, in some treatment methods, oneor more openings may be formed in the tooth (e.g., via drilling) toallow some fluid to flow out of the cavity in the tooth 10, and therestrictor can be used to reduce or prevent fluid backflow out of otheropening(s) (e.g., a coronal access opening).

As discussed, the flow restrictor 68 may include a sponge. The spongemay be formed from a material that is not adversely affected bychemicals or irrigation solutions such as, e.g., sodium hypochlorite,used during root canal procedures. The sponge may comprise any suitableporous and/or absorbent material (or materials). For example, the spongemay comprise a porous material (e.g., elastomeric, plastic, rubber,cellulose, fabric, foam, etc.) that can at least partially absorbliquid. The porous material may comprise an open-cell foam or aclosed-cell foam. The foam can comprise polyvinyl foam, polyethylenefoam, polyvinyl alcohol (PVA) foam, urethane foam, cellulose foam,silicone foam, etc. The flow restrictor 68 may comprise a permeable orsemi-permeable membrane. The flow restrictor 68 material may bedeformable and may be capable of deforming to contours of toothsurfaces. In some embodiments, the sponge comprises a material having adensity in a range from about 1 to about 1000 kg/m³, or in a range ofabout 10 to about 400 kg/m³. In some embodiments, the sponge comprises aclosed-cell vinyl foam having a density of about 160 kg/m³ or about 176kg/m³. In other embodiments, a silicone foam can be used.

The sponge can have a tensile strength in a range from about 1 kPa toabout 3000 kPa or in a range of about 50 kPa to about 400 kPa. Thesponge can have an ultimate elongation in a range of about 5% to about800% or in a range of about 50% to about 300%. In some embodiments, thesponge comprises cells and can have a visual cell count in a range ofabout 1 to about 250/cm or in a range from about 10 to about 40/cm. Thefoam may comprise an ester or another type of foam.

(2) Examples of Vents

In some cases the flow restrictor 68 can comprise one or more vents,e.g., openings, pores, channels, lumens, etc. that may permit somepassage of air or liquid. FIG. 12A schematically depicts two examplehandpieces having different arrangements of vents 73 toward the distalend 58 of the handpiece 50. The vents 73 can have any size, shape,and/or configuration. For example, the vents 73 may be circular, oval,elliptical, rectangular, polygonal, etc. Any number of vents can be usedincluding, zero, one, two, three, four, five, or more vents. The vents73 may be disposed on the distal end 58 of the handpiece 50, on the cap70, or elsewhere on the handpiece 50. In various embodiments, the ventsmay be disposed along (and be in fluid communication with) a fluidoutlet and/or a fluid inlet.

FIG. 12B is a top cross-section view of an embodiment of a handpiece 50that schematically illustrates an example configuration of vents 73,which inhibits or prevents air from entering the pulp chamber 28 of thetooth 10. At the center is a pressure wave generator 64 (or a fluidinflow line). The fluid outflow surrounds the pressure wave generator(or fluid inflow line). Two vents 73 are shown that are angled away fromthe pressure wave generator 64 (or fluid inflow line) and angled towardthe direction of fluid flow in the fluid outlet 72 (see, e.g., arrow 94a). In this example, the vents 73 comprise channels or lumens with afirst end 73 a on the outer surface of the handpiece 50, and a secondend 73 b joining the fluid outlet 72. Ambient air can flow from thefirst end 73 a to the second end 73 b and join or be entrained in flowin the fluid outlet 72. Also, as described herein, if fluid pressure inthe tooth chamber becomes too large, fluid in the tooth chamber can flowout the vents 73 (e.g., the fluid can enter the second end 73 b of thevent and leave the handpiece at the first end 73 a of the vent). Forexample, the fluid outlet 72 may have an outlet axis generally along thefluid outflow direction (e.g., the arrow 94 a), and a vent may have avent axis generally along the airflow direction (e.g., the arrow 92 b).In some embodiments, an angle between the vent axis and the outlet axismay be less than about 90 degrees, less than about 60 degrees, less thanabout 45 degrees, less than about 30 degrees, less than about 15degrees, or some other angle. An advantage of some embodiments in whichthe angle is an acute angle is that the ambient airflow 92 b canrelatively smoothly join (or be entrained in) the fluid flow in theoutlet 72. Further, some such embodiments may inhibit ambient air fromflowing against the flow in the outlet 72 and entering the tooth chamber65, where such ambient air may tend to inhibit cavitation effects insome treatments.

The vents 73 can extend from the outside of the handpiece 50 (where theycan communicate with ambient air) to the fluid outlet line 72. In thisexample, the ambient air can flow towards an evacuation or suction unitthat may also be used for removing waste fluid. During treatment, theoutflow line therefore can include both fluid 92 b (e.g., waste fluidfrom the tooth) and ambient air 94 b from the vents 73. In thisembodiment, by angling the vents 73 away from the center of thehandpiece 50 where the pressure wave generator 64 (or inlet 71) isdisposed, ambient air may be less likely to flow into the tooth chamber65 (where the pressure is higher) and more likely to flow toward theoutlet 72 (where the pressure is lower). In some embodiments, the ventscan be positioned with respect to an evacuation line in such a way thatair entrained into the handpiece 50 does not flow over the accessopening of the tooth, where the waste fluid comes out.

The vents 73 can be designed to improve the safety of the fluid platformso that operating fluid pressures within the tooth chamber 65 remain atdesired or safe levels. Use of the vents 73 can allow for a fluidplatform which is open but in which the pressure and fluid flow is atleast partially controlled. Although some closed fluid platforms may berelatively straightforward, in practice, they may require that the fluidinflow and outflow be highly controlled or precisely matched, or thatthe system be equipped with safety valves and/or shutoff switches. Insome cases, such additions to the system not only can complicate thedesign of the system but may raise the number of possible failure pointswithin the system.

System embodiments that are configured with vents 73 may allow the fluidplatform to operate in a controlled and safe way. Additionally, thesimplicity of the design of certain vents 73 can reduce the number ofpotential failure points. Further, some or all of the possible failurepoints may be reduced to failure points which cause little or no hazardto the patient or practitioner.

The use of vents 73 can provide for a self-regulating fluid platform,which depending on the state of the system, may allow air to be drawninto the fluid outflow path or may allow treatment fluid to overflowfrom the treatment area. The size and position of the vents 73 can beconfigured such that the system maintains a safe apical pressure duringthe following scenarios: while there is little or no flow or pressurethrough the inlet 71 or outlet 72, while there is an excess of flow orpressure through the inlet 71 or outlet 72, while there is a deficiencyof flow or pressure through the inlet 71 or outlet 72, or combinationsof the above scenarios.

In various embodiments, some or all of the following designconsiderations may be used in configuring vents 73 for a particularhandpiece. The vents 73 can be placed along the fluid outlet path, awayfrom the fluid inlet path, such that little or no air can be drawn intothe tooth chamber 65. For example, the vents 73 can be designed suchthat air entering a fluid outflow line flows towards an evacuation unit;thereby inhibiting air from flowing toward the pulp chamber 28 of tooth,as air in the pulp chamber 28 may reduce the efficacy of treatment insome cases. The vents 73 can be placed relatively close to the distalend 58 of the handpiece 50. The vents 73 should not be placed too faraway from the tooth such that during treatment, or in case of anyfailures, the treatment fluid does not build up too much static pressure(positive or negative) inside the tooth and cause adverse effects (e.g.due to elevation difference or flow resistance in the outflow line). Insome embodiments, the fluid outlet 72 may have a distal end in the fluidretainer 66. The vents 73 may be placed about 0 to about 5 mm from theend of the fluid outlet 72, about 0 to about 25 mm from the end of thefluid outlet 72, or about 0 to about 100 mm from the end of the fluidoutlet 72, or any other value. In some embodiments, rather than beingmeasured from the end of the fluid outlet 72, the aforelisted distancesmay be measured with respect to an occlusal surface of the tooth or theendodontic access opening of the tooth.

In other embodiments, the vents 73 can be placed along the fluid inflowpath (e.g., the fluid inlet side of the fluid retainer) and not alongthe fluid flow path. For example, in cases when fluid pressure in thetooth chamber rises toward or above a threshold (e.g., due to a blockageor clogging of the fluid outlet), a vent disposed along the fluid inflowpath may open to shunt fluid out of the inflow path before such fluidwould be delivered to the tooth chamber, which can at least partiallyalleviate the pressure rise. Some embodiments can utilize vents on boththe fluid inflow and the fluid outflow paths (e.g., vents disposed alongthe fluid inlet and along the fluid outlet).

In some embodiments, the shape of the vents 73 can have a relativelylarge aspect ratio (e.g., the vent may have an elongated shape asopposed to a circle of the equivalent area). A vent 73 with a relativelylarge aspect ratio may enable the vent 73 to avoid spilling fluid duringnormal operation (e.g., due to liquid surface tension) while providingair flow along the suction line. The height of the vents may be betweenabout 0 to 1 mm, about 0 to 3 mm, about 0 to 10 mm, or about 0 to 20 mm.The width of the vents may be between about 0 to 2 mm, about 0 to 6 mm,or about 0 to 20 mm. The aspect ratio (e.g., ratio of width to height)of the vent may be about 1:1, 1.25:1, 1.5:1, 2:1, 2.5:1, 3:1, or higher.The aspect ratio may be larger than about 1.5:1, larger than about 2:1,larger than about 2.5:1, or larger than about 3:1. Some vents may becircular or nearly circular (e.g., aspect ratio of about 1:1). In someembodiments, some vents that are closer to the distal end 58 of thehandpiece 50 (e.g., closer to the tooth during treatment) are moreelongated than some vents farther from the distal end 58 (e.g., fartherfrom the tooth during treatment). In various embodiments, the area ofeach vent can be in a range from about 0.5 mm² to 4 mm², about 0.1 mm²to 3 mm², about 0.01 mm² to 10 mm², or larger (e.g., up to about 100mm²).

Multiple vents 73 may be used, for example, from 2 to 10, 2 to 50, orhigher. It may be advantageous to have more than one vent spaced awayfrom at least one other vent for the following some or all of thefollowing reasons: to inhibit accidental blockage of a vent 73, torelieve pressure exerted via an additional suction system applied to avent 73 (e.g., a hand-held dental suction tube operated by a dentalpractitioner or assistant), to maintain the size of each vent 73 smallenough to reduce waste fluid from spilling out of a vent 73 duringnormal operation (e.g., using surface tension), and/or to provide theair flow along the fluid outlet 72. Multiple vents 73 can also be usedto accommodate different positioning scenarios for the handpiece orfluid platform, e.g., left side of jaw, right side of jaw, upper teeth,or lower teeth). Multiple vents 73 can also help ensure that the fluidplatform functions as desired when there are internal or externalobstructions to fewer than all of the vents 73.

Accordingly, in various embodiments, the vents 73 may be properly sized,shaped, and arranged to allow for some or all of the following scenarios(or other scenarios). In some of these scenarios, the system can beconfigured so that little or no pressure is exerted on the pulp chamber.

(1) Waste treatment fluid suctioned through an outflow conduit; noexternal dental suction (e.g., no dental assistant providing externalsuction outside of the tooth): If the waste treatment fluid producedduring the procedure is actively suctioned through the outflow conduit,the vents can allow air to enter the handpiece and further enter theoutflow conduit. The vents can be properly balanced to maintain fluid inthe tooth while not spilling fluid into the mouth. For example, if thecross-sectional area of the vents is too large, treatment solutionintroduced into the tooth may enter the vents and might spill into themouth. If the cross-sectional area of the vents is too small, treatmentsolution may be suctioned out of the tooth, which may reduce cleaningeffectiveness.

(2) Waste treatment fluid suctioned through the outflow conduit;external suction provided by the dental assistant: In this scenario, thedental assistant is actively using a dental suction wand to suction nearthe outside the handpiece. The vents may be sized and shaped such thatan external suction source (e.g., the dental suction wand) hasrelatively little effect on treatment solution inside the handpiece.

(3) No active suction through the outflow conduit; no external dentalsuction: In this scenario, the operator may not have connected theoutflow conduit to an evacuation unit or the fluid outlet may havebecome blocked or clogged. The waste treatment fluid can spill or flowthrough the vents into the patient's mouth (and may be suctioned out bya dental assistant). Fluid may be maintained in the tooth.

(4) No active suction through the outflow conduit; external suctionprovided by the dental assistant: In this scenario, an operator has notconnected the outflow conduit to the evacuation unit, but a dentalassistant is suctioning fluid spilled through the vents into the mouth.Fluid can still be maintained in the mouth.

In other implementations, the vents 73 may include one or more one-wayor check valves configured with a cracking pressure(s) to allow fluidfrom the tooth chamber 65 to leave (e.g., if the fluid pressure in thetooth chamber 65 exceeds the cracking pressure) while preventing ambientair from entering the tooth chamber 65 (unless the pressure in the toothchamber 65 becomes too low).

In various implementations, some or all of the foregoing designconsiderations may depend on several parameters including, e.g., theoperating pressure and flow rate of the evacuation units used with thesystem, the treatment fluid flow rate, the diameter of the fluid outflowline, etc. The number, size, location, shape, and/or configuration ofthe vents 73 may vary in different embodiments. More than one possibledesign of vents 73 may function adequately for a certain set ofoperating parameters, and the design may be selected to achieve oroptimize one or more of the foregoing design considerations (or otherdesign objectives).

(vii) Additional Examples of Liquid Jet Devices

FIG. 9 schematically illustrates an embodiment of a handpiece 50 thatincludes a fluid inlet 71 to deliver fluid to the guide tube 100, whichcan be disposed in the tooth chamber 65. As discussed, the fluid canemerge as a high-velocity jet beam 60, interact with ambient fluid inthe tooth chamber, strike an impingement surface 110 at the distal endof the guide tube 100, and disperse as a spray 90 to generate pressurewaves 67. The handpiece 50 also includes a fluid outlet 72 for removingfluid from the tooth 10. For example, the fluid outlet 72 can be fluidlycoupled to a suction line or evacuation system commonly found in dentaloffices.

FIG. 10A is a cross-section view and FIG. 10B is a top view thatschematically illustrate an example of a fluid platform 61 that can beapplied to a tooth (e.g., on the flat surface of a tooth seal 75, ifused). In this example, the fluid platform 61 includes a fluid retainer66 including a pressure wave generator 64 (e.g., liquid jet) and a fluidoutlet 72 comprising two vents 73. The fluid retainer 66 can be attachedto the tooth with a rubber dam clamp 130. In this example, an elongatedhandpiece is not used, and the fluid retainer 66 can be maneuvered intoposition manually by the dental practitioner. The rubber dam clamp 130can be clamped to the fluid retainer 66 and the tooth under treatment(and/or adjacent teeth) when the fluid platform 61 (or the pressure wavegenerator 64) is in the desired position for treatment.

FIG. 11 schematically illustrates an alternative example of a fluidplatform 61 that can be applied to a tooth 10. In this example, thefluid retainer 66 is placed on the tooth seal 75 (if used) of the toothunder treatment and can be held in place by the patient biting down onthe fluid platform 61 with the opposing tooth. In some embodiments, arubber dam clamp 130 may additionally be used (see, e.g., FIGS. 10A and10B). In this embodiment, the fluid retainer includes a pressure wavegenerator 64 (e.g., a liquid jet), and a fluid outlet 72 comprisingvents 73.

2. Additional Examples of Pressure Wave Generators

As has been described, a pressure wave generator can be any physicaldevice or phenomenon that converts one form of energy into pressurewaves within the treatment fluid. Many different types of pressure wavegenerators (or combinations of pressure wave generators) are usable withembodiments of the systems and methods disclosed herein.

(i) Mechanical Energy

Pressure wave generators can include liquid jet devices. Mechanicalenergy pressure wave generators can also include rotating objects, e.g.miniature propellers, an eccentrically-confined rotating cylinder, aperforated rotating disk, etc. These types of pressure wave generatorscan also include vibrating, oscillating, or pulsating objects such assonication devices that create pressure waves via piezoelectricity,magnetostriction, etc. In some pressure wave generators, electric energytransferred to a piezoelectric transducer can pressure waves in thetreatment fluid. In some cases, the piezoelectric transducer can be usedto create acoustic waves having ultrasonic frequencies.

(ii) Electromagnetic Energy

An electromagnetic beam of radiation (e.g., a laser beam) can propagateenergy into the tooth chamber, and the electromagnetic beam energy canbe transformed into pressure waves as it enters the treatment fluid. Forexample, at least some of the electromagnetic energy may be absorbed bythe fluid (e.g., water) in the tooth chamber, which can generatelocalized heating and pressure waves that propagate in the fluid. Thepressure waves generated by the electromagnetic beam can generatephoto-induced or photo-acoustic cavitation effects in the fluid. Theelectromagnetic radiation from a radiation source (e.g., a laser) can bepropagated to the tooth chamber by an optical waveguide (e.g., anoptical fiber), and dispersed into the fluid at a distal end of thewaveguide (e.g., a shaped tip of the fiber, e.g., a conically-shapedtip). In other implementations, the radiation can be directed to thetooth chamber by a beam scanning system.

The wavelength of the electromagnetic energy may be in a range that isstrongly absorbed by water molecules. The wavelength may in a range fromabout 300 nm to about 3000 nm. In some embodiments, the wavelength is ina range from about 400 nm to about 700 nm, about 700 nm to about 1000 nm(e.g., 790 nm, 810 nm, 940 nm, or 980 nm), in a range from about 1micron to about 3 microns (e.g., about 2.7 microns or 2.9 microns), orin a range from about 3 microns to about 30 microns (e.g., 9.4 micronsor 10.6 microns). The electromagnetic energy can be in the ultraviolet,visible, near-infrared, mid-infrared, microwave, or longer wavelengths.

The electromagnetic energy can be pulsed or modulated (e.g., via apulsed laser), for example with a repetition rate in a range from about1 Hz to about 10 kHz. The pulse energy can be in a range from about 1 mJto about 1000 mJ. The pulse width can be in a range from about 10 μs toabout 500 μs, about 1 ms to about 500 ms, or some other range. In somecases, nanosecond pulsed lasers can be used with pulse rates in a rangefrom about 100 ns to about 500 ns. The foregoing are non-limitingexamples of radiation parameters, and other repetition rates, pulsewidths, pulse energies, etc. can be used in other embodiments.

The laser can include one or more of a diode laser, a solid state laser,a fiber laser, an Er:YAG laser, an Er:YSGG laser, an Er,Cr:YAG laser, anEr,Cr:YSGG laser, a Ho:YAG laser, a Nd:YAG laser, a CTE:YAG laser, a CO₂laser, or a Ti:Sapphire laser. In other embodiments, the source ofelectromagnetic radiation can include one or more light emitting diodes(LEDs). The electromagnetic radiation can be used to excitenanoparticles (e.g., light-absorbing gold nanorods or nanoshells) insidethe treatment fluid, which may increase the efficiency of photo-inducedcavitation in the fluid. The treatment fluid can include excitablefunctional groups (e.g., hydroxyl functional groups) that may besusceptible to excitation by the electromagnetic radiation and which mayincrease the efficiency of pressure wave generation (e.g., due toincreased absorption of radiation). During some treatments, radiationhaving a first wavelength can be used (e.g., a wavelength stronglyabsorbed by water) followed by radiation having a second wavelength notequal to the first wavelength (e.g., a wavelength less strongly absorbedby water). For example, in some such treatments, the first wavelengthmay help create bubbles in the tooth fluid, and the second wavelengthmay help disrupt the tissue.

The electromagnetic energy can be applied to the tooth chamber for atreatment time that may be in a range from about one to a few seconds upto about one minute or longer. A treatment procedure may include one toten (or more) cycles of applying electromagnetic energy to the tooth. Afluid platform may be used to circulate a fluid in the tooth chamberduring the treatment process, which advantageously may inhibit heatingof the tooth (which may cause discomfort to the patient). The fluidplatform may include a fluid retainer to assist retaining fluid in thetooth. The fluid retainer may inhibit splashback of fluid, which canoccur by hydraulic self-ejection during certain pulsed laser treatments.The circulation of treatment fluid (e.g., water with a tissue dissolvingagent) by the fluid platform may bring fresh treatment fluid to tissueand organic matter as well as flush out dissolved material from thetooth. In some treatments using electromagnetic radiation, circulationof the treatment fluid can increase the effectiveness of the cleaning(as compared to a treatment with little or no fluid circulation).

In some implementations, electromagnetic energy can be added to otherpressure wave generation modalities. For example, electromagnetic energycan be delivered to a tooth chamber in which a mechanical energypressure wave generator (e.g., a liquid jet) is used to generate theacoustic waves.

(iii) Acoustic Energy

Acoustic energy (e.g., ultrasound) can be generated from electric energytransferred to an ultrasound transducer or an ultrasonic tip (or file orneedle) that creates pressure waves in the treatment fluid. Theultrasonic transducer may comprise a piezoelectric crystal thatphysically oscillates in response to an electrical signal or amagnetostrictive element that converts electromagnetic energy intomechanical energy. The transducer can be disposed in the treatmentfluid, for example, in the fluid inside the pulp cavity or in the fluidcontained within the fluid platform (but outside the pulp cavity). Anexample of the power spectrum that can be produced by an ultrasonicdevice is shown in FIG. 2B-2. Ultrasonic sources can provide acousticpower in a frequency range from about 20 kHz to about 40 kHz (e.g.,about 30 kHz) in various embodiments. Sonic (e.g., frequencies less thanabout 20 kHz such as about 1 kHz to 8 kHz) or megasonic energy (e.g.,frequencies greater than about 1 MHz) can be used in some embodiments.

(iv) Further Properties of Some Pressure Wave Generators

A pressure wave generator 64 can be placed at a desired location withrespect to the tooth. The pressure wave generator 64 creates pressurewaves 67 within the fluid inside the tooth (the generation of pressurewaves 67 may or may not create or cause cavitation). The pressure waves67 propagate throughout the fluid inside the tooth, with the fluid inthe tooth serving as a propagation medium for the pressure waves 67. Thepressure waves 67 can also propagate through tooth material (e.g.,dentin). It is believed, although not required, that as a result ofapplication of a sufficiently high-intensity pressure wave, acousticcavitation may occur. The collapse of cavitation bubbles may induce,cause, or be involved in a number of processes described herein such as,e.g., sonochemistry, tissue dissociation, tissue delamination,sonoporation, and/or removal of calcified structures. A smear layer in acanal space includes a layer of dentin, organic and inorganic debris,and bacteria created during instrumentation of canals (e.g., byendodontic files). The cavitation effects discussed herein can beeffective at removing the smear layer. In some embodiments, the pressurewave generator 64 may be configured such that the pressure waves 67(and/or cavitation) do not substantially break down natural dentin inthe tooth. The pressure wave field by itself or in addition tocavitation may be involved in one or more of the abovementionedprocesses.

In some implementations, the pressure wave generator generates primarycavitation, which creates pressures waves, which may in turn lead tosecondary cavitation. The secondary cavitation may be weaker than theprimary cavitation and may be non-inertial cavitation. In otherimplementations, the pressure wave generator generates pressure wavesdirectly, which may lead to secondary cavitation.

In various implementations, the pressure wave generator 64 can bedisposed in suitable locations. For example, the pressure wave generator64 can be attached to a handpiece 50 that can be maneuvered in apatient's mouth. The distal end of the pressure wave generator 64 can bedisposed inside the pulp cavity 26, for example, in close proximity tothe canals on the pulp chamber 28 floor. In such implementations, for agiven amount of energy emitted by the pressure wave generator 64, thepressure waves 67 may have an increased effect on cleaning,decalcifying, and removing a smear layer within the canals and thepulpal chamber the closer the pressure wave generator 64 is to thecanals. In some cases, the distal end of the pressure wave generator 64is located at a distance of about 1 mm to about 3 mm from the pulpchamber floor. The desired distance may depend on the modality used tocreate the pressure waves 67 in the fluid (e.g., mechanical,electromagnetic, acoustic). In other embodiments, the distal end of thepressure wave generator 64 may be located inside a root canal 30. Forexample, the guide tube 100 can comprise a flexible material that can bedirected down a canal toward the apex of the canal. In one embodiment,the distal end of the pressure wave generator 64 is positioned outsidethe pulp cavity 26 but exposed to fluid in the pulpal cavity. In anotherembodiment, the distal end of the pressure wave generator 64 ispositioned inside the root canal space 30.

In some embodiments in which the pressure wave generator 64 (or fluidinlet 71) causes a stream of fluid to flow into the root canal, dynamicpressurization of the root canal may occur, which in turn may causeperiapical extrusion of materials in some patients. The parametersinfluencing dynamic pressurization can include, e.g., the direction,shape, and speed of the stream of fluid with respect to the canalorifices and also the pulp cavity shape and topology. Also, in someimplementations, if the pressure wave generator 64 enters the root canalorifice and substantially blocks the root canal pathway, the blockagemay decelerate or even stop the set of physicochemical phenomena used toclean and disinfect the root canals. Thus, as discussed above, thepressure wave generator 64 can be designed such that the distal end ofthe pressure wave generator 64 is located at a desired or prescribedlocation in the pulp chamber 28 of the teeth.

The energy source that provides the energy for the pressure wavegenerator 64 can be located outside the handpiece, inside the handpiece,integrated with the handpiece, etc.

B. Examples of Methods and Apparatus for Endodontic Treatment with FluidPlatforms

FIG. 13A schematically illustrates an access opening 25 formed in atooth 10. A drill or grinding tool can initially be used to make theopening 25 in the tooth 10. The opening 25 may extend through the enamel22 and the dentin 20 to expose and provide access to pulp in the pulpcavity 26. The opening 25 may be made in a top portion of the crown 12of the tooth 10 or in another portion such as a side of the crown 12,near the cemento-enamel junction 15, or in the root 16 below the gum 14.The opening 25 may be sized and shaped as needed to provide suitableaccess to the diseased pulp and/or some or all of the canal spaces 30. Afluid platform 61 or handpiece 50 can be applied or attached to thetooth so as to enable an endodontic procedure in the tooth.

(1) Examples of a Tooth Seal

In other methods, an (optional) tooth seal 75 can be formed on the toothto provide a flat surface 76 to which a fluid platform 61 or handpiece50 can be applied. FIG. 13B schematically illustrates an embodiment ofthe tooth seal 75 applied to a perimeter of a crown 12 of the tooth 10of FIG. 13A. As will be described, the upper surface 76 of the toothseal 75 can be made substantially flat after application and removal ofa flat plate.

The tooth seal 75 can be used to temporarily fill grooves, dents, orimperfections of the occlusal surface of the tooth or to create asubstantially flat surface 76 that a cap 70 of a fluid platform 61 orhandpiece 50 can engage with. A tooth seal 75 can facilitate awater-tight and/or air-tight seal that substantially inhibits entry intoand/or escape of liquid or air from the pulp chamber 28. The tooth seal75 may be used to form a substantially hermetic seal of the pulp chamber28. The tooth seal 75 can help the cap 70 engage with a tooth withsubstantial crown irregularities or irregularities due to other reasons,thereby sealing irregularities that the cap 70 would not be able toeasily fill in by itself.

In some instances where a tooth 10 is missing a wall, or has decay, thetooth seal 75 (or one or more dental composite materials) may be used torebuild the damaged or decayed portion of the tooth 10 before formingthe tooth seal 75 on the crown 12. FIG. 13C schematically illustrates anembodiment of a tooth seal 75 applied to a tooth 10 in which a portion77 of the crown 12 is missing due to decay or damage. The tooth seal 75has been used to cover or build up the portion 77 of the crown 12 sothat the tooth seal 75 (and the non-decayed portion of the tooth) form asubstantially complete chamber for subsequent fluid treatments.

The tooth seal 75 can comprise a material that can easily be removedfrom the tooth after use. The material may be reshaped using tools suchas dental bur, scalpel, etc. The material can be substantially pliableor semi-flexible that will set in a relatively short time (e.g., lessthan about 30 seconds) either by itself or with curing (e.g. via curinglight). Examples of materials that can be used, alone or in combination,to form the tooth seal 75 include silicones, impression materials, 3MImprint™ Bite, Jet Blue Bite by Cobelle Whaledent®, etc.

An example method for applying the tooth seal 75 to a tooth is asfollows. An endodontic access opening 25 in the tooth can be made, e.g.,using standard endodontic access preparation techniques, substantiallyas used in conventional root canal procedures. In some embodiments, thecanals can be prepared using standard techniques. In other embodiments,the canals are not prepared. Tooth seal material can be applied on theocclusal surface of the tooth and/or also around perimeter of the crown12. Decayed or diseased portions of the tooth may be built up using thetooth seal material or other composite material. A flat plate can beapplied to the tooth seal material, e.g., by pushing the plate onto thematerial, thereby creating a substantially flat surface beneath theplate. The operator can wait until the material sets or can use a curinglight to cure the material (if photo-curable). The flat plate can beremoved from the tooth seal material. If any of the material haspenetrated the pulp chamber 28 or blocked the endodontic access opening25, the material can be removed with a tool (e.g. dental bur). A fluidplatform 61, handpiece 50, or cap 70 can be applied to the flat surfaceof the tooth material and the endodontic procedure can begin.

In some such methods, the tooth seal 75 may be applied to the toothbefore the endodontic access opening 25 is formed. The endodontic accessopening 25 can then be formed for both dentin and the tooth sealmaterial. In this case, using a substantially transparent material maybe preferred to improve visibility for endodontic access.

The tooth seal material may adhere to the tooth by itself or may beattached to the tooth using adhesive. In some methods, the tooth sealmaterial may be applied in such a way so that it flows over and into arubber dam clamp, which upon setting/curing enforces the attachment ofthe tooth seal material onto the tooth. In some such methods, thematerial at least partially adheres to the tooth while engaging with therubber dam clamp.

An example method of applying a tooth seal 75 to a tooth comprisesapplying a tooth seal material to a surface of the tooth, andplanarizing a surface 76 of the tooth seal material. In someembodiments, the method includes forming an access opening 25 in thetooth, wherein the access opening 25 can be formed prior to applying thetooth seal material or after applying the tooth seal material. In someembodiments, planarizing the surface of the tooth comprises apply a flatsurface to the tooth seal material. The method may include curing thetooth seal material. The method may include removing the flat surfacefrom the tooth seal material. The method may include building up aportion of a tooth using a composite material or the tooth sealmaterial.

(2) Examples of a Tooth Sizer

In some methods, the distal end of a fluid inlet 71 and/or a pressuregenerator 64 can be positioned inside the pulp chamber 28 with thedistal end at a desired distance from a root canal orifice. Bypositioning the distal end of the fluid inlet 71 at a suitable locationin the pulp chamber 28, patient safety may be improved by, e.g., notover-pressurizing root canal spaces 30. By positioning the distal end ofthe pressure wave generator 64 at a suitable location in the pulpchamber 28, effectiveness of the acoustic waves 67 at generatingcavitation and cleaning effects may be increased. Further, fluidcirculation in portions of the tooth chamber (e.g., circulation in aroot canal space) may be enhanced. In various methods, the verticaldistance between the distal end of the fluid dispenser and/or thepressure wave generator 64 and the highest point of the pulpal floor maybe in a range from about 0 to 1 mm, 0 to 5 mm, 5 to 10 mm, 10 to 15 mm,15 to 30 mm, 0 to 30 mm, or some other range.

With reference to the examples shown in FIGS. 14A and 14B, a set or kitof sizers can be used to measure the distance between the substantiallyflat surface 76 created by the tooth seal material on the occlusalsurface and the highest point on the pulpal floor.

FIG. 14A schematically illustrates an example of a sizer 132 insertedinto a pulp chamber 28 of an example tooth 10. In this example, thesizer 132 is too large for the pulp chamber 28. FIG. 14B schematicallyillustrates another example of a sizer 132 inserted into the pulpchamber 28 of a tooth 10. In this example, the sizer 132 is the desiredsize for the pulp chamber 28. The sizer 132 can be moved laterallyacross the width of the chamber, with the solid lines showing the sizer132 in a first position and the dashed lines showing the sizer 132 in adifferent position in the pulp chamber 28.

In the example shown in FIGS. 14A and 14B, the sizer 132 has a handle134 (which may be similar to that of endodontic files), a pin 140 whoselength varies among sizers of different sizes, and a disk 136 separatingthe handle 134 from the pin 140. The handle 134 can be grasped in thefingers or by dental pliers. The distal surface 138 of the disk 136 canbe substantially flat. The sizer pin 140 can be inserted into the pulpchamber 28 of the tooth 10. The dental practitioner may determine thedepth or size of the pulp chamber 28 by inserting sizers 132 withdifferent pin lengths into the pulp chamber 28. In FIG. 14A, the sizerpin 140 is too long for the pulp chamber 28, because the sizer disk 136extends above the flat surface 76 of the tooth seal 75 when a distal end142 of the pin 140 touches the pulp chamber floor. A shorter sizer pin140 can be selected and moved laterally around the pulp chamber 28. Thisprocess can be repeated until a sizer pin 140 is found that does notcontact the pulp floor as it is moved around the pulp chamber 28. Thesizer 132 having the correct or desired length may have the longest pin140 that does not come in contact with the pulp floor when the sizerdisk 136 is placed over and slid laterally (schematically shown by soliddouble-headed arrow 146 in FIG. 14B) on the flat surface 76 of the toothseal 75. FIG. 14B shows a sizer 132 with an appropriate pin length forthe illustrated tooth 10, because the distal end 142 of the pin 140 ispositioned an appropriate height above the pulp floor (as indicated bythe horizontal dashed line 144). This sizer 132 can be used to establishthe depth of the pulp chamber 28.

In another implementation, a single sizer 132 can be used. The sizer pin140 can be marked or scaled with measurement indicia, and the sizer disk136 can be adjustable and configured to move up or down relative to thepin 140. The dental practitioner can insert the sizer 132 into the pulpchamber 28 and move the sizer disk 136 until it contacts the uppersurface 76 of the tooth seal 75. The sizer 132 is then removed from thepulp chamber 28, and the position of the disk 136 relative to themeasurement indicia provides a measurement of the depth of the pulpchamber 28. The distal end of the pressure wave generator (or fluidinlet) may be positioned at a depth slightly less than the measureddepth of the pulp chamber 28 so that the distal end is at a desiredheight above the pulp chamber floor (e.g., from about 1 mm to a 5 mmabove the floor)

In other embodiments, a ruler or depth gauge graduated with suitableindicia can be inserted into the pulp chamber 28 to measure the distancefrom an upper surface (e.g., the flat surface 76 of a tooth seal 75, ifused) to a lower surface (e.g., the floor of the pulp chamber). In otherembodiments, a radiograph (e.g., X-ray) of the tooth may be taken, andthe size or depth of the pulp chamber 28 determined from the radiograph.

An example method of determining a depth of a tooth chamber 65 comprisesproviding a kit comprising a set of sizers, where each sizer in the setis configured to measure a different tooth chamber depth. The methodincludes repeatedly inserting different sizers into the tooth chamber 65to determine the depth. In some embodiments of the method, the depth isdetermined as the longest sizer that does not contact the pulpal floor.In some embodiments, the method includes moving a sizer laterally aroundthe tooth chamber 65.

(3) Examples of a Cap and Sealer

The fluid retainer 66 may include a cap 70 (and an optional sealer 68)that can be sized so that a distal end of a fluid inlet 71 or pressurewave generator 64 is at a desired location in the tooth chamber 65. Insome systems, each sizer 132 can be associated with a cap 70 that can beapplied to the tooth. As described, the cap 70 can, in some cases, beattached to the distal end 58 of the handpiece 50 or manually applied tothe tooth 10 (without using the handle of a handpiece). The cap 70 canbe used so that the distal end of the fluid inlet 71 or pressure wavegenerator 64 is located at the desired height above the pulp floor(indicated by the horizontal dashed line 144 in FIG. 15C) when thehandpiece 50 is applied to the tooth seal 75. The size increments of thecaps may be substantially equal to the size increments of the pins onthe sizers. After the depth of the pulp chamber 28 is determined usingthe sizers 132, an appropriately-sized cap can be selected and(optionally) mounted on the handpiece 50 or fluid platform 61. The cap70 can be attached to the handpiece 50 chemically (e.g. glued, using anadhesive), mechanically (e.g., snapped or screwed), magnetically (e.g.,by making the cap 70 and the distal end of the handpiece of oppositemagnetic polarities), or by a combination of the foregoing.Alternatively, the cap 70 can be attached (e.g., glued) onto tooth.

In some embodiments, the cap 70 can include a sealer 68, which may be aflexible gasket (e.g., a sponge) that helps maintain water-tight orair-tight coupling between the cap 70 and the tooth seal 75, so thatfluid does not leak out of the tooth 10 during treatment. A flexiblesealer 68 may be able to accommodate movement of the handpiece 50 on thetooth as the dental practitioner maneuvers the handpiece into position.The sealer 68 can be disposed at the distal end of the cap 70 (see,e.g., FIG. 3A) or may be disposed inside the cap 70 (see, e.g., FIG.3B). In some embodiments, the sealer functions as the flow restrictor 68and inhibits backflow or splashing from the tooth chamber 65, helpsretain fluid in the tooth chamber 65, and can permit air to flow into asuction line.

The sealer 68 can comprise sponge (e.g., a closed-cell foam). The sealermaterial advantageously may be able to withstand chemicals (e.g.,bleach) used during endodontic treatments. The sealer 68 can be formedfrom material that is elastic to properly seal between the handpiece andthe tooth. Examples include a sponge, e.g., polyvinyl foam,polyethylene, polyvinyl alcohol (PVA), cellulose foam, silicone foam,etc. Other examples include silicone, elastomer, rubber, latex, etc. Inone embodiment, a material with substantially little acoustic dampeningis used.

In some methods, a tooth seal is not used, and the cap 70 of thehandpiece 50 (or fluid platform 61) may be applied directly to thetooth. In some such methods, the sealer 68 can provide adequate sealingbetween the cap 70 and the tooth 10 to inhibit flow of treatment fluidand organic matter from the tooth chamber 65 during treatment.

The cap 70 may have an internal chamber 69 that allows fluid to flowfrom the tooth chamber 65 into a fluid outlet 72. The internal chamber69 may have an opening 98 that may be large enough so that a portion ofa pressure wave generator 64 can pass through the opening (see, e.g.,FIG. 12B). The opening 98 can be configured to be sufficiently large toallow the waste fluid to leave the pulp cavity 26 without substantialpressurization of the cavity (or canal apices) and can be configured tobe small enough not to interfere with the sealing of the pulpal cavity.In some embodiments, the size of the opening can be adjusted based atleast in part on the flow rate of the fluid dispensed into the chamber.In some embodiments, the opening comprises a substantially circularopening. In some such embodiments, the guide tube 100 can be disposed inthe opening 98 (e.g., in the middle of the opening 98; see, e.g., FIG.12B). In some embodiments, the effective area of the opening is in arange from about 5 mm² to 15 mm². The opening may have an area in arange from about 1 mm² to 25 mm². The sealer 68 may substantiallysurround the opening at the distal end of the cap 70 (see, e.g., FIG.11).

The fluid connection created between the cap 70 and the tooth 10 (ortooth seal 75) may be flexible in nature such that the connection canaccommodate movements in the handpiece related to the tooth whilemaintaining the fluid connection. In some embodiments, the cap 70 isformed from a durable, biocompatible material, and the sealer 68 is usedto accommodate movements and provide a good fluid connection. In otherembodiments, the cap 70 may be made from one or more materials withdifferent elasticities, permeabilities, and/or degrees of firmness. Forexample, a softer, more permeable material can be used to engage withthe tooth, reducing (or potentially eliminating) the need for a separatesealer 68. Caps can have different shapes depending on which tooth isbeing treated (e.g., molar, incisor, canine, etc.).

In some cases, a relatively small amount of force is used to create apositive seal between the tooth 10 (or tooth seal 75) and the cap 70.For example, in the case of a handpiece 50, the pressure applied to thehandpiece 50 to form the seal can be low enough for the operator tocomfortably apply during the procedure. In case where the handpiece isnot handheld, the cap 70 can be applied to the tooth 10 (or tooth seal75) without excessive clamping/holding force (e.g., by the patientbiting down). The cap 70 can be used throughout the procedure and can beconfigured to withstand chemical exposure (such as irrigants introducedduring the procedure).

(4) Examples of a Handpiece Applied to a Tooth Seal

FIGS. 15A, 15B, and 15C schematically illustrate a handpiece 50 appliedto a tooth seal 75 on a tooth 10. FIG. 15A is a side view, FIG. 15B is apartial cutaway view that shows a pressure wave generator 64 disposed inthe tooth chamber 65, and FIG. 15C is a close-up view showing the distalend 58 of the handpiece 50 and the pressure wave generator 64.

The distal end 58 of the handpiece 50 includes a cap 70 that wasselected as described above so as to position the distal end of thepressure wave generator 64 at a desired distance above the pulp chamberfloor (shown by the horizontal dashed line 144 in FIG. 15C). In thisexample, the cap 70 includes a sealer 68 to assist in providing asubstantially water-tight connection between the cap 70 and the uppersurface 76 of the tooth seal 75 (see, e.g., FIGS. 15B and 15C). FIG. 15Cshows that, in this example, the handpiece 50 includes the pressure wavegenerator 64 (a liquid jet) and a vented fluid outlet 72, 73. In thisexample, treatment fluid enters the cavity via the liquid jet and isremoved by the fluid outlet 72.

(5) Examples of Treatment Procedures

FIGS. 16A, 16B, 16C, and 16D are flowcharts illustrating examples oftechniques that may be used during various endodontic procedures. Thesetechniques are intended to be illustrative and not limiting. Thetechniques can be performed in any suitable sequence. None of thetechniques is necessary or indispensable to every endodontic procedure.Also, techniques can be added or removed.

In FIG. 16A, at block 220, anesthetics can be injected into the patientto numb the tooth area. At block 222, a rubber dam can be applied to thetooth area and the rubber dam can be disinfected. At block 224, thedental practitioner may remove decay from the tooth 10 and, ifnecessary, build up walls of the tooth chamber 65, e.g., with acomposite material or a tooth seal material. For example, the dentalpractitioner may decide to build up a wall due to decay or damage to thetooth structure (see, e.g., FIG. 13C). At block 226, the practitionermay then perform an endodontic access to provide an opening 25 into thetooth chamber. The access may be coronal, buccal, lingual, or any othertype of access. In some procedures, multiple openings 25 can be formed,e.g., one opening to provide access to the tooth chamber for a fluidinlet or pressure wave generator and a second opening to permit fluid todrain from the tooth chamber 65.

In FIG. 16B, at block 228, a tooth seal 75 may be applied to the tooth10 to provide a substantially flat surface 76 on which the fluidplatform 61 or a handpiece 50 can be applied. In some procedures, thetooth seal 75 may not be used, and, for example, a flow restrictor(e.g., a sponge) may be applied to the access opening to retain fluid inthe tooth chamber. At block 230, the depth of the tooth chamber 65 canbe measured. For example, the depth can be measured using a kit of oneor more tooth sizers (see, e.g., FIGS. 14A and 14B) or using a graduatedgauge or file. Once the desired size of the tooth chamber 65 isdetermined, a corresponding cap can be selected from a kit of caps atblock 232. The cap may be attached to a fluid retainer (e.g., on adistal end of a handpiece 50). The cap 70 can be sized so that a distalend of a fluid inlet 71 or a distal end of a pressure wave generator 64is at a desired position in the tooth 10, e.g., a desired distance abovethe pulp chamber floor. The cap 70 may include a sealer 68 (e.g., spongeor foam) to provide a substantially water-tight or air-tight connectionbetween the cap 70 and the tooth seal 75 (or tooth, if a tooth seal isnot used). As discussed herein, the cap need not

In FIG. 16C, at block 234, the pulp chamber 28 and the coronal portionsof the root canal spaces may be cleaned, if desired, for example, tofacilitate use of an apex locator to measure working length of thecanals. At block 236, the working length of a root canal space can bemeasured, for example, with an apex locator, an instrument (e.g., afile), or a radiograph (e.g., an X-ray). For example, the working lengthcan be a measure of the length of a canal space from an apicalconstriction to a cusp on an occlusal surface of the tooth 10. Ifdesired, at block 238, the dental practitioner can shape the rootcanals, e.g., to enlarge or shape the canal space as desired. At block240, the tooth chamber 65 can be cleaned. For example, a fluid retainer66 can be applied to the tooth and used to circulate a cleaning solution(e.g., antiseptic or antibiotic) in the tooth chamber 65 (see, e.g.,FIG. 3A). A pressure wave generator 64 can be activated to generateacoustic waves 67 that propagate through the tooth 10 (see, e.g., FIG.2A). The acoustic waves 67 can generate acoustic cavitation, which mayeffectively clean the root canals of the tooth 10. In some procedures,the fluid flowing from the tooth 10 may be monitored to determine whenthe cleaning is complete (see, e.g., FIG. 3C).

In FIG. 16D, at block 242, the tooth chamber 65 may be at leastpartially obturated with an obturation material to substantially filland seal the canal spaces. In some procedures, obturation is optional,because the cleaning may be so complete that there is little likelihoodof future infection or reinfection. By not obturating the tooth chamber65, the duration and cost of the procedure may be reduced for thepatient. At block 244, the access openings 25 may be sealed, forexample, with a coronal seal (if a coronal access opening is used). Atblock 246, a crown can be restored over the access opening.

FIG. 17 is a flowchart illustrating an example method of using adegassed fluid during an endodontic procedure. In this example method,at block 248, a degassed fluid is introduced into a tooth chamber 65.The degassed fluid may be delivered from a source of degassed fluid suchas, e.g., a reservoir (e.g., bottle) or may be delivered as the outputfrom a degassing unit. The degassed fluid may be introduced into thetooth chamber using a fluid inlet or fluid introducer in variousembodiments. The degassed fluid may circulate in the tooth chamber. Thedegassed fluid may have a sufficiently low percentage of dissolvedgasses so as to penetrate openings in the dentin of the tooth having adimension less than about 500 microns, less than about 250 microns, lessthan about 100 microns, less than about 50 microns, less than about 25microns, less than about 10 microns, less than about 5 microns, or someother value. The use of degassed fluid may inhibit formation of gasbubbles in the tooth chamber.

Energy may be delivered into the degassed fluid. For example, at block250, acoustic waves may be generated in the degassed fluid in the tooth.The acoustic waves may, but need not, generate acoustic cavitation influid in the tooth. The acoustic waves may propagate through thedegassed fluid to surrounding dentin structure of the tooth. Block 250can be optional in some procedures, as the flowing degassed fluid may beused to irrigate tooth tissue. Also, the degassed fluid may includesolutes (e.g., an antiseptic, antibiotic, or decalcifying agent) thatmay clean the tooth chamber. The degassed fluid may inhibit theformation of gas bubbles in the tooth chamber, and may allow thedegassed fluid to flow into small tooth spaces (e.g., tubules, smallcanals) to provide more effective cleaning.

In some implementations, an apparatus for treating a tooth can be usedto implement embodiments of the method shown in FIG. 17. The apparatuscan comprise a degassed liquid source, and a fluid introducer that isconfigured to supply fluid from the degassed liquid source to a toothchamber formed in a tooth.

III. Additional Example Aspects of Pressure Wave Tissue Cleaning

It is believed, although not required, that some or all of the effectsdescribed below may be at least in part responsible for advantageouseffects, benefits, or results provided by various implementations of thetreatment methods and systems described herein. Accordingly, variousembodiments of the systems disclosed herein can be configured to providesome or all of these effects.

In the following description, unless a different meaning is indicated,the following terms have their ordinary and customary meaning. Forexample, a chemical reaction front may generally refer to an interfacebetween the tissue and the solution which contains a chemical such as atissue dissolving agent. Tissue may refer to all types of cells existingin the tooth as well as bacteria and viruses. Calcified tissue may referto calcified pulp, pulp stones, and tertiary dentin. Bubbles includesbut is not limited to bubbles created due to a chemical reaction,dissolved gas remaining in the fluid after degassing (if used) andreleased as bubbles in the fluid, and any bubbles which are introducedinto the tooth due to imperfect sealing.

Tissue cleaning treatments may utilize one or more of thephysicochemical effects described herein to clean and remove tissueand/or calcified tissue from a tooth chamber. In some cleaningtreatments, the combination of (1) pressure waves (e.g., generation ofacoustic cavitation), (2) circulation of fluid in the tooth chamber(e.g., macroscopic eddies and flows), and (3) chemistry (e.g., use of atissue dissolving agent, use of degassed fluids) can provide highlyeffective cleaning. Accordingly, certain embodiments of the systemsdisclosed herein utilize a pressure wave generator to generate theacoustic waves, a fluid platform (e.g., fluid retainer) to retaintreatment fluid in the tooth chamber and to enable circulation of thetreatment fluid, and a treatment fluid that is degassed or includes achemical agents such as a tissue dissolving agent.

A. Acoustic Waves

A pressure wave generator can be used to generate pressure waves thatpropagate through the fluid in the tooth chamber (and the tooth). Uponirradiation of a fluid with high intensity pressure waves (e.g., sonicor ultrasonic frequencies), acoustic cavitation may occur. As has beendescribed herein, the implosive collapse of the cavitation bubbles canproduce intense local heating and high pressures with short lifetimes.Therefore, in some treatment methods, acoustic cavitation may beresponsible for or involved in enhancing chemical reactions,sonochemistry, sonoporation, tissue dissociation, tissue delamination,as well as removing the bacteria and/or the smear layer from the rootcanals and tubules. The effects of enhancing chemical reaction viavibrations or sonochemistry will be described below in the section onchemistry.

Sonoporation is the process of using an acoustic field (e.g., ultrasonicfrequencies in some cases) to modify the permeability of the cell plasmamembrane. This process may greatly expedite the chemical reaction. Itmay be advantageous if the acoustic field has a relatively broadbandwidth (e.g., from hundreds to thousands of kHz). Some frequencies(e.g., low frequency ultrasound) may also result in cellular rupture anddeath (e.g., lysis). This phenomenon may kill bacteria which mightotherwise reinfect the tooth. Pressure waves and/or acoustic cavitationmay loosen the bond between cells and/or may dissociate the cells.Pressure waves and/or acoustic cavitation may loosen the bond betweencells and dentin and/or delaminate the tissue from the dentin.

For removing calcified tissue, pressure waves may induce sonochemistryand microscopic removal of calcified structures due to shock wavesand/or microjets created as a result of cavitation bubble implosion.Pressure waves may break microscopic calcified structures throughstructural vibrations. If a chemical (e.g., a chelating agent such as,e.g., EDTA) is used for this procedure, the pressure waves may enhancethe chemical reaction.

Certain properties of the system can be adjusted to enhance the effectsof the acoustic waves. For example, properties of the fluid including,e.g., surface tension, boiling or vapor temperature, or saturationpressure can be adjusted. A degassed fluid with a reduced dissolved gascontent can be used, which may reduce the energy loss of pressure wavesthat may be generated by hydrodynamic cavitation or any other sources.The fluid can be degassed, which may help preserve the energy of thepressure waves and may increase the efficiency of the system.

B. Fluid Circulation

Some treatment systems and methods use diffusion and/or ultrasonicallyenhanced diffusion of reactants and byproducts to and away from thechemical reaction front. However, due to the relatively short time scaleof the reaction process, a faster mechanism of reactant delivery such as“macroscopic” circulation, convection, vorticity, or turbulence may beadvantageous in some of the embodiments disclosed herein. For example,fluid inflow into the tooth chamber may induce a macroscopic circulationin the pulp cavity (see, e.g., FIG. 3B). A liquid jet device not onlymay create pressure waves but may also induce circulation as the jetand/or spray enter the tooth chamber. Other pressure wave generators canproduce fluid circulation via their interaction with ambient fluid(e.g., via localized heating of the fluid, which may induce convectioncurrents and circulation).

Fluid circulation with a time scale comparable to (and preferably fasterthan) that of chemical reaction may help replenish the reactants at achemical reaction front and/or may help to remove reaction byproductsfrom the reaction site. The convective time scale, which may relate toeffectiveness of the convection or circulation process, can be adjusteddepending on, e.g., the location and characteristics of the source ofcirculation. The convective time scale is approximately the physicalsize of the tooth chamber divided by the fluid speed in the toothchamber. Introduction of circulation generally does not eliminate thediffusion process, which may still remain effective within a thinmicroscopic layer at the chemical reaction front. Fluid circulation maycreate flow-induced pressure oscillations inside the root canal whichmay assist in delaminating, loosening, and/or removing larger piecestissue from the root canal.

For removing calcified tissue, fluid circulation may create flow-inducedpressure oscillations inside the root canal which may assist in removinglarger pieces of calcified structures from the root canal.

Certain properties of the system can be adjusted to enhance the effectsof the circulation in the tooth. For example, the location of the sourceof circulation inside the tooth, the source flow characteristics such asshape (e.g. planar vs. circular jets) or velocity and/or direction of afluid stream, and the fluid kinematic viscosity may be adjusted. Thecirculation may also be effected by the anatomy of the tooth or thecanal orifice or root canal size. For example, a narrow root canal withconstrictions may have a lower solution replenishment rate than a widecanal with no constrictions. If the source of convection/circulation isplaced near the pulp chamber floor, a tooth with a smaller pulp chambermay have stronger circulation than one with a larger pulp chamber.Convection-induced pressure exerted at the periapical region of thetooth may be controlled to reduce or avoid extrusion of the treatmentfluid into the periapical tissues. Large magnitude vacuum or lowpressure in the tooth may cause discomfort in some patients. Thus, theproperties of the fluid platform (e.g., vents, sponges, flowrestrictors, etc.) can be adjusted to provide a desired operatingpressure range in the tooth chamber.

C. Chemistry

A tissue dissolving agent (e.g., sodium hypochlorite) may be added tothe treatment fluid to react with tissue. Tissue dissolution may be amulti-step and complex process. Dissolution of sodium hypochlorite inwater can include a number of reactions such as, e.g., the sodiumhypochlorite (bleach) reaction, a saponification reaction withtriglycerides, an amino acid neutralization reaction, and/or achloramination reaction to produce chloramine. Sodium hypochlorite andits by-products may act as dissolving agents (e.g. solvents) oforganics, fats, and proteins; thereby, degrading organic tissue in sometreatments.

Sodium hypochlorite may exhibit a reversible chemical equilibrium basedon the bleach reaction. Chemical reactions may occur between organictissue and sodium hypochlorite. For example, sodium hydroxide can begenerated from the sodium hypochlorite reaction and can react withorganic and fat (triglycerides) molecules to produce soap (fatty acidsalts) and glycerol (alcohol) in the saponification reaction. This mayreduce the surface tension of the remaining solution. Sodium hydroxidecan neutralize amino acids forming amino acid salts and water in theamino acid neutralization reaction. Consumption of sodium hydroxide canreduce the pH of the remaining solution. Hypochlorous acid, a substancethat can be present in sodium hypochlorite solution, can releasechlorine that can react with amino groups of proteins and amino acids toproduce various chloramines derivatives. For example, hypochlorous acidcan react with free amino acids in tissue to form N-chloro amino acidswhich can act as strong oxidizing agents that may have higher antisepticactivity than hypochlorite.

Chemical(s) in the fluid, depending on their type, may affect thesurface tension of the solution, which in turn may modify the cavitationphenomenon. For example, solution of an inorganic chemical such as,e.g., sodium hypochlorite in water, may increase the ion concentrationin the solution which may increase the surface tension of the solution,which may result in stronger cavitation. In some cases, the magnitude ofa cavitation inception threshold may increase with increasing surfacetension, and the cavitation inducing mechanism (e.g., a pressure wavegenerator) may be sufficiently intense to pass the threshold in order toprovide inception of cavitation bubbles. It is believed, but notrequired, that once the cavitation threshold is passed, increasedsurface tension may result in stronger cavitation. Reducing thedissolved gas content of a fluid (e.g., via degassing) can increase thesurface tension of the fluid and also may result in stronger cavitation.Addition of chemicals, agents, or substances (e.g., hydroxyl functionalgroups, nanoparticles, etc.) to the treatment may increase theefficiency of conversion of a pressure wave into cavitation, and suchchemoacoustic effects may be desirable in some treatment procedures.

In some methods, a chemical, such as sodium hypochlorite, may causesaponification. The removal of bubbles created or trapped inside theroot canals (or tubules) may be accelerated due to local reduction ofsurface tension at the chemical reaction front as a result ofsaponification. Although in some methods it may be desirable to have arelatively high surface tension at the pressure wave source (e.g. insidethe pulp chamber), inside the canals it may be beneficial to havelocally reduced surface tension to accelerate bubble removal. Thisphenomenon may happen as tissue dissolving agent(s) react with thetissue. For example, sodium hypochlorite can act as a solvent degradingfatty acids, transforming them into fatty acid salts (soap) and glycerol(alcohol) that can reduce the surface tension of the remaining solutionat the chemical reaction front.

A number of variables or factors may be adjusted to provide effectivecleaning. For example, each chemical reaction has a reaction ratedetermining the speed of reaction. The reaction rate may be dependent onseveral parameters including temperature. The concentration of reactantscan be a factor and may affect the time for the reaction to complete.For instance, a 5% sodium hypochlorite solution generally may be moreaggressive than a 0.5% sodium hypochlorite solution and may tend todissolve tissue faster.

The refreshment rate of reactants may be affected by some or all of thefollowing. Bubbles may form and stay at the chemical reaction front(e.g., due to surface tension forces) and may act as barriers at thechemical reaction front impeding or preventing fresh reactants fromreaching the reaction front. Accordingly, circulation of the treatmentfluid can help remove the bubbles and the reaction byproducts, and mayreplace them with fresh treatment fluid and fresh reactants. Thus, useof an embodiment of the fluid platform that can provide fluidcirculation in the tooth chamber advantageously may improve the cleaningprocess.

Heat may increase the chemical reaction rate and may be introducedthrough a variety of sources. For example, the treatment solution may bepreheated before delivery to the tooth chamber. Cavitation, exothermicchemical reactions, or other internal or external dissipative sourcesmay produce heat in the fluid, which may enhance, sustain, or increasereaction rates.

Sonication of the fluid may increase chemical reaction rates oreffectiveness. For example, upon irradiation of a fluid (e.g., water)with high intensity pressure waves (including, e.g., sonic or ultrasonicwaves, or broad spectrum acoustic power produced by a liquid jet)acoustic cavitation may occur. The implosive collapse of the cavitationbubbles can produce intense local heating and high pressures with shortlifetimes. Experimental results have shown that at the site of thebubble collapse, the temperature and pressure may reach around 5000 Kand 1000 atm, respectively. This phenomenon, known as sonochemistry, cancreate extreme physical and chemical conditions in otherwise coldliquids. Sonochemistry, in some cases, has been reported to enhancechemical reactivity by as much as a million fold. In cases whereacoustic cavitation does not occur (or occurs at a relatively lowamplitude), the vibration of reactants, due to the pressure waves, mayenhance the chemical reaction as it assists in replacing the byproductsby fresh reactants.

For removing calcified tissue, a decalcifying agent (e.g., an acid suchas, e.g., EDTA or citric acid) may be added to the treatment fluid. Thedecalcifying agent may remove calcium or calcium compounds from thetooth dentin. The substances remaining after treatment with thedecalcifying agent may be relatively softer (e.g., gummy) than prior totreatment and more easily removable by the fluid circulation andacoustic waves.

IV. Additional Examples and Embodiments

Additional examples and embodiments of apparatus, methods, andcompositions will be described. The examples are intended to illustrateand not limit the disclosure. Accordingly, all possible combinations andsubcombinations of the features described below can be included in otherembodiments. Additional features can be added or features can beremoved. The features can be rearranged. In the procedures and methods,the operations or acts are not limited to the disclosed sequence, andthe operations or acts may be performed in a different sequence.

Fluids as described herein generally means liquids, and the liquids mayinclude a certain amount of dissolved gas. For example, a fluid caninclude water (having a normal dissolved gas (e.g., air) content as canbe determined from Henry's law for the appropriate temperature andpressure conditions) or degassed water, which can have a reduceddissolved gas content as compared to water with a normal dissolved gascontent. A tooth chamber may include at least a portion of any space,opening, or cavity of the tooth, including any portion of spaces,openings, or cavities already present in the tooth (either by normal orabnormal dentin and/or tissue structure or by degeneration,deterioration, or damage of such structure) and/or any portion ofspaces, openings, or cavities formed by a dental practitioner during atreatment. For example, the tooth chamber may include at least a portionof the pulp chamber and may also include at least a portion of one ormore of the following: an access opening to the tooth, a root canalspace, and a tubule. In some treatments, the tooth chamber can includesome or all of the root canal spaces, accessory canals, and tubules inthe tooth. In some procedures, the access opening can be formed apart orseparately from the tooth chamber.

1. Examples of Procedures with Fluid Platforms and Pressure WaveGenerators

In one aspect, a procedure for treating a tooth is disclosed. Theprocedure comprises forming at least an access opening into a toothchamber in a tooth, introducing fluid into at least a portion of thetooth chamber to provide a fluid level in the tooth, and using a fluidretainer to inhibit uncontrolled flow of fluid from the tooth chamber.The procedure may further comprise inserting a pressure wave generatorinto the tooth chamber and at least partially below the fluid level,activating the pressure wave generator in the tooth chamber to produceacoustic energy waves in the fluid, and maintaining the fluid in thetooth chamber such that the pressure wave generator remains submergedbelow the fluid level during at least a portion of the procedure.

In some aspects, the procedure may further comprise introducing fluidcomprising introducing a degassed liquid. The procedure may furthercomprise using the fluid retainer to inhibit uncontrolled flow of fluid,including retaining sufficient fluid within the tooth chamber to permitthe acoustic energy waves to propagate within the fluid, wherein theacoustic energy waves retain sufficient energy to create at least somefluid cavitation within the tooth chamber. Using the fluid retainer maycomprise substantially inhibiting air flow into the tooth chamber,additionally comprising removing waste fluid from the tooth chamber, andsubstantially inhibiting leakage of introduced fluid, waste fluid, andorganic material from the tooth chamber. In another aspect, using thefluid retainer may comprise permitting at least some of the fluid toleave the tooth chamber while substantially inhibiting air from enteringthe chamber.

In other aspects, using the fluid retainer may involve positioning a caparound the tooth chamber such that the cap substantially closes theaccess opening into the tooth chamber. The procedure may furthercomprise positioning the cap on a tooth seal region of the tooth,wherein the tooth seal region comprises a tooth seal, and whereinpositioning the cap on the tooth seal region comprises planarizing asurface of the tooth seal. In some embodiments, using the fluid retainermay also involve positioning a flow restrictor around the tooth chamberand within the cap. The procedure may further comprise positioning thecap on the tooth seal region, which may substantially seal the toothchamber so as to allow for controlled ingress and egress of fluid. Usingthe fluid retainer may also comprise providing a vent to regulate fluidpressure within the tooth chamber. Providing the vent may includepermitting at least some air flow to be entrained with fluid removedfrom the tooth chamber. In some other aspects, providing the ventincludes permitting at least some air flow to be entrained with fluidremoved from the tooth chamber and may further comprise providing afluid outlet configured to permit fluid to flow from the tooth chamber.

Using the fluid retainer may maintain the fluid pressure within thetooth at pressures below a predetermined pressure level. The proceduremay further comprise activating the pressure wave generator, which maycomprise activating a fluid jet. Activating the pressure wave generatormay also comprise activating a laser, and activating the pressure wavegenerator may create at least some fluid cavitation in the toothchamber.

2. Examples of Procedures Using Energy Beams Impacting an InstrumentSurface

In another aspect, a procedure for treating a tooth is disclosed. Theprocedure comprises forming at least an access opening into a toothchamber in a tooth, introducing fluid into at least a portion of thetooth chamber to provide a fluid level in the tooth, and inserting aninstrument surface into the tooth chamber, the instrument surface belowthe fluid level during at least a portion of the procedure. Theprocedure may further comprise impacting the instrument surface with anenergy beam to produce acoustic energy waves in the fluid, andmaintaining the fluid in the tooth chamber such that the instrumentsurface remains submerged below the fluid level during at least aportion of the procedure.

In other aspects, introducing the fluid comprises introducing a degassedliquid. Further, in some embodiments, impacting the instrument surfacewith the energy beam produces sufficient acoustic energy for theacoustic energy waves to cause at least some fluid cavitation within thetooth chamber, and may further comprise substantially clearing the toothchamber of organic matter. In another aspect, the procedure may compriseactivating a pressure wave generator to create the energy beam.Activating the pressure wave generator may comprise activating a fluidjet. Activating the fluid jet may include introducing a high velocitybeam of degassed liquid into the tooth chamber. In other aspects,activating the fluid jet comprises impacting the instrument surface withthe jet. Inserting the instrument surface into the tooth chamber mayinclude inserting a distal portion of an instrument into the toothchamber. The instrument may include a channel having an opening in adistal portion of the channel. In some aspects, activating the fluid jetincludes propagating the fluid jet through the channel. Impacting theinstrument surface with the fluid jet may comprise deflecting the fluidjet from the instrument surface and discharging the fluid jet throughthe opening in the channel.

In another embodiment, activating the pressure wave generator comprisesactivating a laser, while in another aspect, activating the pressurewave generator comprises activating an ultrasonic device. In yet anotheraspect, activating the pressure wave generator comprises activating amechanical stirrer. In yet another aspect, activating the pressure wavegenerator creates at least some fluid cavitation in the tooth chamber.

3. Examples of Procedures with Fluid Jet Beams

In yet another aspect, a procedure for treating a tooth is disclosed.The procedure comprises forming at least an access opening into a toothchamber in a tooth, providing a fluid jet beam by passing fluid throughan orifice, and introducing the fluid jet beam into the tooth chamber,the fluid jet beam discharging from a distal portion of an instrument.The procedure may further comprise providing a fluid level in the tooth,positioning the distal portion of the instrument in the tooth chamber,the distal portion of the instrument below the fluid level during atleast a portion of the procedure, and maintaining the fluid in the toothchamber such that the distal portion of the instrument remains submergedbelow the fluid level during at least a portion of the procedure.

In other aspects, introducing the fluid jet beam into the tooth chambermay include producing acoustic energy wave. Providing the fluid jet beammay comprise imparting sufficient energy to the fluid jet beam toproduce acoustic energy waves. The procedure may further comprisemaintaining the fluid at a sufficient fluid level to permit propagationof the acoustic energy waves and imparting sufficient energy to thefluid jet beam to produce at least some fluid cavitation within thetooth chamber. The method may further comprise substantially clearingthe tooth chamber of organic matter.

In other embodiments, introducing the fluid jet beam may includeimpacting an impingement surface with the fluid jet beam to produceacoustic energy waves in the fluid. In another aspect, introducing thefluid jet beam comprises passing the fluid jet beam through a channel ofthe instrument, and may further comprise providing an impingementsurface near the distal portion of the instrument, and impacting theimpingement surface with the fluid jet beam. The procedure may furthercomprise providing a vented fluid outlet to enable fluid removal fromthe tooth chamber and to limit overpressurization, underpressurization,or both overpressurization and underpressurization of the tooth chamber.The procedure may further comprise providing a vented fluid inlet toenable fluid delivery to the tooth chamber and to limitoverpressurization, underpressurization, or both overpressurization andunderpressurization of the tooth chamber. In some aspects, impacting theimpingement surface and discharging the fluid jet beam may produceacoustic energy waves that cause at least some fluid cavitation withinthe tooth chamber. In some embodiments, providing a fluid jet beam maycomprise producing a high velocity beam of degassed liquid.

4. Examples of Procedures Using Broadband Frequency Pressure WaveGenerators

In yet another aspect, a procedure for treating a tooth is disclosed.The procedure comprises forming at least an access opening into a toothchamber in a tooth, introducing fluid into at least a portion of thetooth chamber to provide a fluid level in the tooth, and inserting atleast a portion of a pressure wave generator into the tooth chamber, theat least a portion of the pressure wave generator below the fluid levelduring at least a portion of the procedure. The procedure may furthercomprise producing with the pressure wave generator acoustic energywaves of a broadband spectrum in the fluid, and maintaining the fluid inthe tooth chamber such that the portion of the pressure wave generatorremains submerged below the fluid level.

In other embodiments, introducing the fluid may comprise introducingdegassed liquid into at least the portion of the tooth chamber. Theprocedure may further comprise producing sufficient acoustic energy tocause at least some fluid cavitation within the tooth chamber. In someaspects, inserting at least the portion of the pressure wave generatorinto the tooth chamber comprises providing a fluid jet beam within thetooth chamber, and may further comprise impacting an impingement surfacewith the fluid jet beam.

In some aspects of the procedure, a substantial amount of the acousticenergy waves propagate at frequencies above about 0.5 kHz, while inother aspects, a substantial amount of the acoustic energy wavespropagate at frequencies above about 1 kHz, about 10 kHz, or about 100kHz. In some aspects of the procedure, the acoustic energy waves have apower with a bandwidth of at least 50 kHz, while in other aspects, theacoustic energy waves have a power with a bandwidth of at least 100 kHz.In some embodiments, the acoustic energy waves have a power with abandwidth of at least 500 kHz, while in other embodiments, the acousticenergy waves have a power with a bandwidth between about 50 kHz andabout 500 kHz. Additionally, inserting at least the portion of thepressure wave generator into the tooth chamber may comprise activating alaser. In other aspects, inserting at least the portion of the pressurewave generator into the tooth chamber may comprise activating anultrasonic device. In yet other aspects, inserting at least the portionof the pressure wave generator into the tooth chamber may compriseactivating a mechanical stirrer.

5. Examples of Procedures Using Pressure Wave Generators with EnergyAbove 1 kHz

In yet another embodiment, a procedure for treating a tooth isdisclosed. The procedure comprises forming at least an access openinginto a tooth chamber in a tooth, introducing fluid into at least aportion of the tooth chamber to provide a fluid level in the tooth, andinserting at least a portion of a pressure wave generator into the toothchamber below the fluid level. The procedure may further compriseproducing with the pressure wave generator acoustic energy waves, atleast a substantial amount of the acoustic energy waves havingfrequencies of 1 kHz or greater, and maintaining the fluid in the toothchamber such that the portion of the pressure wave generator remainssubmerged below the fluid level during at least a portion of theprocedure.

In other aspects, introducing the fluid may comprise introducingdegassed liquid into at least the portion of the tooth chamber, and theprocedure may also comprise producing sufficient acoustic energy tocause at least some fluid cavitation within the tooth chamber. Further,inserting at least the portion of the pressure wave generator into thetooth chamber may comprise providing a fluid jet beam within the toothchamber, and may further comprise impacting an impingement surface withthe fluid jet beam. In some aspects of the procedure, the acousticenergy waves may propagate at least at frequencies above about 0.5 kHz,while in other aspects, the acoustic energy waves may propagate at leastat frequencies at least above about 1 kHz, 10 kHz, 50 kHz, or 100 kHz.Inserting at least the portion of the pressure wave generator into thetooth chamber may also comprise activating a laser, and in some otherembodiments, inserting at least the portion of the pressure wavegenerator into the tooth chamber comprises activating an ultrasonicdevice. Additionally, inserting at least the portion of the pressurewave generator into the tooth chamber may comprise activating amechanical stirrer.

6. Examples of Apparatus Having a Fluid Retainer

In another aspect, an apparatus for treating a tooth is disclosed. Theapparatus comprises a fluid retainer configured to be applied to thetooth to substantially retain fluid in a tooth chamber in the tooth, anda pressure wave generator having a distal portion. The distal portion ofthe pressure wave generator can be configured to be inserted into thetooth chamber.

The distal portion of the pressure wave generator may be insertedthrough the fluid retainer so as to be inserted into the tooth chamber.For example, the distal portion may be inserted through a sponge-likematerial that retains fluid in the tooth chamber. The distal portion ofthe pressure wave generator may be attached to a distal portion of thefluid retainer so that when the fluid retainer is applied to the tooth,the distal portion of the pressure wave generator is inserted into thetooth chamber.

The fluid retainer may be configured to be applied to the tooth, forexample, by placing the retainer on an occlusal surface of the tooth(with or without an adhesive or flow restrictor such as a sponge), bycovering or plugging an access opening to the tooth chamber, by wrappinga portion of the fluid retainer around the tooth, etc.

The fluid retainer can substantially retain fluid in the tooth chamber.For example, the fluid retainer can retain most or substantially all ofthe fluid in the tooth chamber by providing a water-resistant sealbetween the retainer and the tooth. The fluid retainer may, but neednot, retain all the fluid in the tooth. For example substantiallyretaining fluid in the tooth chamber does not require that there be noamount of leakage of the fluid from the tooth chamber. The fluidretainer can be applied to the tooth to reduce or minimize the amount offluid that leaks into the patient's mouth during treatment, which mayimprove patient safety and experience since some fluids can containcaustic or unpleasant tasting substances.

In other embodiments, the apparatus may comprise a body. The body caninclude the fluid retainer and one or more vents configured to permit atleast some of the fluid to leave the tooth chamber while inhibiting airfrom entering the tooth chamber. The vent can be configured to permit atleast some air flow to be entrained with fluid leaving the toothchamber. In some aspects, the body may further comprise a fluid outletconfigured to permit fluid to flow from the tooth chamber. The body mayfurther comprise a handpiece. Additionally, the pressure wave generatormay be configured to generate acoustic energy waves, and the fluidretainer may be configured to retain sufficient fluid within the toothchamber to permit acoustic energy waves to propagate within the fluid. Asubstantial amount of the acoustic energy waves generated by thepressure wave generator can retain sufficient energy to create at leastsome fluid cavitation within the tooth chamber. The fluid retainer cancomprise at least one vent to regulate pressure within the toothchamber. The at least one vent may be disposed along a fluid inlet,along a fluid outlet, or on both the fluid inlet and the fluid outlet.

In some aspects, the fluid retainer comprises a flow restrictor. In someembodiments, the flow restrictor may comprise a sponge, and in someembodiments, the flow restrictor may comprise a vent. In yet otherembodiments, the fluid retainer may be configured to substantiallyinhibit air flow into the tooth chamber. The fluid retainer may includeat least one outlet. The fluid retainer may be configured tosubstantially inhibit leakage of fluid, organic material, or both fromthe tooth chamber. The fluid retainer may also be configured to permitat least some of the fluid to leave the tooth chamber, and tosubstantially inhibit air from entering the tooth chamber. In someaspects, the fluid retainer may comprise a cap, wherein the cap may bepositioned around the tooth chamber such that the cap substantiallycloses an access opening into the tooth chamber. The cap may also bepositioned on a tooth seal region of the tooth, wherein the cap mayinclude a planar surface that mates to a tooth seal having a planarsurface.

In some embodiments, the fluid retainer may comprise a flow restrictorpositioned around the tooth chamber and within the cap, and in otheraspects, the cap may substantially seal the tooth chamber so as to allowfor controlled ingress and egress of fluid. In other aspects, the fluidretainer may be configured to maintain the fluid pressure within thetooth at pressures below a predetermined pressure level. In yet otheraspects, the pressure wave generator may comprise one or more devicesselected from the group consisting of: a fluid jet, a laser, amechanical stirrer, and an ultrasonic device. The pressure wavegenerator may also be configured to create at least some fluidcavitation in the tooth chamber. In some embodiments, the fluid retainermay comprise one or more vents configured to permit at least some of thefluid to leave the tooth chamber while inhibiting air from entering thetooth chamber, wherein the pressure may be regulated to be above about−300 mmHg and below about +300 mmHg.

7. Examples of Apparatus Including Pressure Wave Generators Having aReverberation Surface

In yet another embodiment, an apparatus for treating a tooth isdisclosed. The apparatus comprises a pressure wave generator having anenergy guide and a distal portion with a reverberation surface. Theenergy guide can be arranged relative to the reverberation surface so asto direct a beam of energy onto the reverberation surface to produceacoustic pressure waves. The distal portion can be sized or shaped tofit within a tooth chamber in a tooth.

The energy guide can be arranged relative to the reverberation surface,for example, by being positioned or spaced a distance away from thereverberation surface and oriented so that the beam of energy canintercept the reverberation surface.

In some aspects, the beam of energy may comprise a fluid jet beam. Thefluid jet beam may comprise degassed liquid. In other embodiments, thepressure wave generator comprises one or more devices selected from thegroup consisting of: a fluid jet source, a laser, an ultrasonic device,and a mechanical stirrer. Further, the energy guide may also comprise aguide tube having a channel with an opening on the distal portion of theguide tube. The pressure wave generator can be configured to outputsufficient energy so as to cause at least some fluid cavitation withinthe tooth chamber.

8. Examples of Apparatus with Pressure Wave Generators Including anImpact Surface

In another aspect, an apparatus for treating a tooth is disclosed. Theapparatus comprises a pressure wave generator having a fluid beamforming portion including an orifice and an impact surface. The impactsurface may be spaced from the orifice and positioned such that an axisthrough the orifice extends to the impact surface. The impact surfacemay be configured to be inserted into a tooth chamber in a tooth.

In other aspects, the fluid beam forming portion may be configured toform a fluid jet beam that will substantially impact the impact surface.The fluid beam forming portion may be configured to form a fluid jetbeam having sufficient energy to cause at least some cavitation withinthe tooth chamber when the fluid jet beam impacts the impact surface.The apparatus may further comprise a guide tube having a channelextending along the axis and configured to permit the fluid jet beam toflow therethrough.

In some aspects, the apparatus may also comprise a fluid retainerpositioned around the pressure wave generator such that the fluidretainer substantially closes an access opening into the tooth chamber.The fluid retainer may be configured to retain at least some fluidwithin the tooth chamber. The apparatus may further comprise a body. Thebody can comprise one or more vents configured to permit at least someof the fluid in the tooth chamber to leave the tooth chamber whilesubstantially inhibiting air from entering the tooth chamber. Further,the one or more vents may be configured to permit at least some air flowto be entrained with fluid leaving the tooth chamber. In some aspects,the body may further comprise a fluid outlet configured to permit fluidto flow from the tooth chamber. The body can comprise a handpiece.

9. Examples of Apparatus with Broadband Pressure Wave Generators

In one aspect, an apparatus for treating a tooth is disclosed. Theapparatus comprises a pressure wave generator having at least a distalportion configured to be inserted into a tooth chamber in a tooth andsubmerged in fluid in the tooth chamber. The pressure wave generator mayproduce acoustic pressure waves having a broadband spectrum.

The distal portion of the pressure wave generator configured to beinserted into a tooth chamber can include the distal portion being sizedor shaped to fit into the tooth chamber.

In other aspects, the broadband spectrum comprises power at least atfrequencies above about 1 kHz, while in yet other aspects, the broadbandspectrum may comprise power at least at frequencies above about 10 kHz.In some embodiments, the broadband spectrum may comprise power at leastat frequencies above about 100 kHz or above about 500 kHz. The broadbandspectrum may have a bandwidth greater than about 50 kHz. The broadbandspectrum may have a bandwidth greater than about 100 kHz. Additionally,the broadband spectrum may have a bandwidth greater than about 500 kHz.

The pressure wave generator may comprise one or more devices selectedfrom the group consisting of: a fluid jet, a laser, a mechanicalstirrer, and an ultrasonic device. In some embodiments, the distalportion of the pressure wave generator may comprise an impingementsurface, and the pressure wave generator may also comprise a liquid jetconfigured to impact the impingement surface. The apparatus may furthercomprise a source of degassed liquid configured to provide liquid forthe liquid jet. The apparatus may also comprise a fluid retainerpositioned around the pressure wave generator such that the fluidretainer substantially closes an access opening into the tooth chamber.The fluid retainer may be configured to substantially inhibit flow ofair into the tooth chamber. In some aspects, the fluid retainer maycomprise a sponge, and in other aspects, the fluid retainer may comprisea vent to regulate fluid pressure within the tooth chamber. In yet otherembodiments, the fluid retainer may comprise a fluid outlet port forremoval of fluid from the tooth chamber. The fluid outlet port mayfurther comprise a vent in fluid communication with the fluid outletport. In other aspects, the vent may be configured to permit air to beentrained into flow of fluid removed from the tooth chamber via thefluid outlet port, and the vent can be further configured to inhibitflow of air into the tooth chamber.

10. Examples of Apparatus with Pressure Wave Generators GeneratingFrequencies Above 1 kHz

In another embodiment, an apparatus for treating a tooth is disclosed.The apparatus comprises a pressure wave generator having at least adistal portion configured to be inserted into a tooth chamber in a toothand submerged in fluid in the tooth chamber. The pressure wave generatormay produce acoustic pressure waves at least having frequencies of 1 kHzor greater. The distal portion of the pressure wave generator configuredto be inserted into a tooth chamber can include the distal portion beingsized or shaped to fit into the tooth chamber.

In some embodiments, the acoustic pressure waves may at least havefrequencies of 10 kHz or greater, while in other embodiments, theacoustic pressure waves may at least have frequencies of 100 kHz orgreater. In other embodiments, the acoustic pressure waves at least havefrequencies of 10 kHz or greater. The acoustic pressure waves may havesubstantial power at frequencies greater than about 1 kHz, greater thanabout 10 kHz, greater than about 100 kHz, or greater than about 500 kHz.Substantial power can include, for example, an amount of power that isgreater than 10%, greater than 25%, greater than 35%, or greater than50% of the total acoustic power (e.g., the acoustic power integratedover all frequencies). In some aspects, the acoustic pressure waves havea bandwidth of at least about 10 kHz. In other aspects, the acousticpressure waves have a bandwidth of at least about 50 kHz, while in someaspects, the acoustic pressure waves have a bandwidth of at least about100 kHz. The pressure wave generator may comprise one or more devicesselected from the group consisting of: a fluid jet, a laser, amechanical stirrer, and an ultrasonic device. In some embodiments, thepressure wave generator comprises a liquid jet configured to impact animpingement surface of the distal portion of the pressure wavegenerator. The liquid jet may comprise a degassed liquid.

11. Examples of Procedures Using Pressure Wave Generators Having anEnergy Outlet in a Fluid

In another aspect, a procedure for treating a tooth is disclosed. Theprocedure comprises forming at least an access opening into a toothchamber in a tooth, inserting fluid into at least a portion of the toothchamber, and providing a pressure wave generator having an energy outletdisposed in the fluid during at least a portion of the procedure. Theprocedure may further comprise positioning the energy outlet such thatpressure waves generated from the outlet are delivered to the fluid andinto the tooth chamber through the fluid. Further, the procedure maycomprise activating the pressure wave generator so as to produceacoustic pressure waves with at least a substantial amount of theproduced acoustic pressure waves having frequencies of 1 kHz or greater.The procedure may further comprise using the pressure wave generator todeliver sufficient energy to the fluid so as to dissociate tissue in thetooth.

In some aspects, inserting fluid may comprise introducing a degassedliquid. Further, in some cases, at least a substantial amount of theproduced acoustic pressure waves may have frequencies of 50 kHz orgreater. Activating the pressure wave generator may comprise activatinga fluid jet beam. The procedure may further comprise impacting animpingement surface with the fluid jet beam. In addition, activating thepressure wave generator may comprise activating a laser, and activatingthe pressure wave generator may also produce acoustic pressure wavesthat create at least some fluid cavitation in the tooth chamber.

12. Examples of Procedures Using Pressure Wave Generators and LimitingApical Pressure

In another aspect, a procedure for treating a tooth is disclosed. Theprocedure comprises forming at least an access opening into a toothchamber in a tooth, inserting fluid into at least a portion of the toothchamber, and providing a pressure wave generator having an energy outletdisposed in the fluid during at least a portion of the procedure. Theprocedure may further comprise positioning the energy outlet such thatenergy generated from the outlet is delivered to the fluid and into thechamber through the fluid, and such that the energy does not create anapical pressure above about 100 mmHg in a canal of the tooth. Theprocedure may further comprise activating the pressure wave generator,maintaining the energy outlet of the pressure wave generator in thefluid during at least part of the procedure, and using the pressure wavegenerator to delivery sufficient energy to the fluid so as to dissociatetissue in the tooth.

In some aspects, the procedure may comprise providing an impingementsurface positioned near the energy outlet. Activating the pressure wavegenerator may comprise forming an energy beam and impacting theimpingement surface with the energy beam. In some cases, the energy beammay comprise a fluid jet beam. In some embodiments, the procedure mayfurther comprise deflecting the fluid jet beam from the impingementsurface when the fluid jet beam impacts the impingement surface. Inaddition, the procedure may comprise positioning the energy outlet suchthat the deflected fluid jet beam passes through the energy outlet. Insome aspects, forming the energy beam may comprise activating a laser,activating an ultrasonic device, or activating a mechanical stirrer. Insome cases, the energy may not create a jet stream of fluid down a canalof the tooth.

13. Examples of Procedures Using Fluid Retainers

In yet another aspect, a procedure for treating a tooth is disclosed.The procedure comprises forming at least an access opening into a toothchamber in a tooth, and applying a fluid retainer onto the tooth. Thefluid retainer may comprise an inner chamber that communicates with thetooth chamber when the fluid retainer is applied to the tooth. Theprocedure may further comprise supplying fluid into at least a portionof the tooth chamber and into at least a portion of the inner chamber ofthe fluid retainer. Further, the procedure may comprise positioning apressure wave generator in the inner chamber such that, during at leastpart of the procedure, an energy outlet of the pressure wave generatorextends into the inner chamber and is disposed within the fluid. Inaddition, the procedure may comprise activating the pressure wavegenerator to produce acoustic energy waves in the fluid in the toothchamber, and using the pressure wave generator to delivery sufficientenergy to the fluid so as to dissociate tissue in the tooth.

In some aspects, supplying fluid may comprise supplying a degassedliquid. The procedure may further comprise using the fluid retainer toinhibit uncontrolled flow of fluid. In some cases, using the fluidretainer to inhibit uncontrolled flow of fluid may include retainingsufficient fluid within the tooth chamber to permit the acoustic energywaves to propagate within the fluid. In addition, the acoustic energywaves may retain sufficient energy to create at least some fluidcavitation within the tooth chamber. Using the fluid retainer mayfurther comprise substantially inhibiting air flow into the toothchamber.

In some embodiments, the procedure may comprise removing waste fluidfrom the tooth chamber. In some cases, using the fluid retainer maysubstantially inhibit leakage of supplied fluid, waste fluid, andorganic material from the tooth chamber. Using the fluid retainer maycomprise permitting at least some of the fluid to leave the toothchamber while substantially inhibiting air from entering the chamber. Insome aspects, using the fluid retainer involves positioning a cap aroundthe tooth chamber such that the cap substantially closes the accessopening into the tooth chamber. In other aspects, the procedure maycomprise positioning the cap on a tooth seal region of the tooth. Thetooth seal region may comprise a tooth seal, and positioning the cap onthe tooth seal region may comprise planarizing a surface of the toothseal.

Using the fluid retainer may involve positioning a flow restrictoraround the tooth chamber and within the cap. Positioning the cap on thetooth seal region may also substantially seal the tooth chamber so as toallow for controlled ingress and egress of fluid. In some cases, usingthe fluid retainer may further comprise providing a vent to regulatefluid pressure within the tooth chamber. Additionally, providing thevent may include permitting at least some air flow to be entrained withfluid removed from the tooth chamber. In some embodiments, the proceduremay also comprise providing a fluid outlet configured to permit fluid toflow from the tooth chamber. Using the fluid retainer may maintain thefluid pressure within the tooth at pressures below a predeterminedpressure level. In some embodiments, activating the pressure wavegenerator may comprise activating a fluid jet or activating a laser. Insome cases, activating the pressure wave generator may create at leastsome fluid cavitation in the tooth chamber.

14. Examples of Procedures Using Auxiliary Chambers

In another embodiment, a procedure for treating a tooth is disclosed.The procedure comprises forming at least an access opening into a toothchamber in the tooth, and providing an auxiliary chamber disposedadjacent the tooth. The auxiliary chamber may comprise an inner orinterior chamber of a fluid retainer. The procedure may further compriseproviding a fluid filling at least a portion of the tooth chamber and atleast a portion of the auxiliary chamber. The fluid may provide a commonenergy transmission medium between the tooth chamber and the auxiliarychamber. The procedure may also comprise inserting an energy outlet of apressure wave generator into the auxiliary chamber so as to extend intoand be immersed in the fluid within the auxiliary chamber. Further, theprocedure may comprise activating the pressure wave generator to produceacoustic energy waves in the fluid in the tooth chamber, and using thepressure wave generator to delivery sufficient energy to the fluid inthe tooth chamber so as to dissociate tissue in the tooth.

In some embodiments, providing an auxiliary chamber may comprisepositioning a fluid retainer around the access opening of the toothchamber. Positioning the fluid retainer may further comprise positioninga cap around the access opening such that the cap substantially closesthe access opening into the tooth chamber. In some aspects, theprocedure may comprise positioning the cap on a tooth seal region of thetooth. In some cases, the tooth seal region may comprise a tooth seal.Further, positioning the fluid retainer may involve positioning a flowrestrictor around the access opening and within the cap. In someembodiments, positioning the cap on the tooth seal region substantiallyseals the tooth chamber and the auxiliary chamber so as to allow forcontrolled ingress and egress of fluid.

The procedure may further comprise providing a vent to regulate fluidpressure within the tooth chamber. In some aspects, providing the ventincludes permitting at least some air flow to be entrained with fluidremoved from the tooth chamber. Additionally, the procedure may compriseproviding a fluid outlet configured to permit fluid to flow from thetooth chamber. Activating the pressure wave generator may compriseactivating a fluid jet or activating a laser. In some cases, activatingthe pressure wave generator creates at least some fluid cavitation inthe tooth chamber.

15. Examples of Apparatus with Fluid Retainers Having an Inner Chamber

In another aspect, an apparatus for treating a tooth is disclosed. Theapparatus comprises a fluid retainer configured to be applied to thetooth to substantially retain fluid in a tooth chamber in the tooth. Thefluid retainer may include an inner chamber. The apparatus may alsocomprise a pressure wave generator having an energy outlet disposedwithin the inner chamber of the fluid retainer. In some cases, when thefluid retainer is applied to the tooth, the inner chamber may bedisposed so as to be in communication with the tooth chamber, and theenergy outlet of the pressure wave generator may be disposed outside thetooth chamber.

In some aspects, the apparatus may comprise a body that includes thefluid retainer and one or more vents configured to permit at least someof the fluid to leave the tooth chamber while inhibiting air fromentering the tooth chamber. The body may comprise an outer housingsubstantially surrounding the fluid retainer. In some aspects, the fluidretainer comprises one or more vents configured to permit at least someof the fluid to leave the tooth chamber while inhibiting air fromentering the tooth chamber. The one or more vents may be configured topermit at least some air flow to be entrained with fluid leaving thetooth chamber. In some embodiments, the body may comprise a fluid outletconfigured to permit fluid to flow from the tooth chamber. The body mayalso comprise a handpiece. In some cases, the pressure wave generatormay be configured to generate acoustic energy waves. Further, the fluidretainer may be configured to retain sufficient fluid within the toothchamber to permit acoustic energy waves to propagate within the fluid. Asubstantial amount of the acoustic energy waves generated by thepressure wave generator may also retain sufficient energy to create atleast some fluid cavitation within the tooth chamber.

In some embodiments, the fluid retainer may comprise a flow restrictor.The flow restrictor may comprise a sponge or a vent. Additionally, thefluid retainer may be configured to substantially inhibit air flow intothe tooth chamber. The fluid retainer may also include at least oneoutlet. In some embodiments, the fluid retainer may be configured tosubstantially inhibit leakage of fluid, organic material, or both fromthe tooth chamber. In yet other aspects, the fluid retainer may beconfigured to permit at least some of the fluid to leave the toothchamber. The fluid retainer may also be configured to substantiallyinhibit air from entering the chamber.

The fluid retainer may comprise a cap. In some aspects, the cap may beconfigured to be positioned around the tooth chamber such that the capsubstantially closes an access opening into the tooth chamber. Further,the cap may be configured to be positioned on a tooth seal region of thetooth, and the cap may also include a planar surface that mates to atooth seal having a planar surface. In some embodiments, the fluidretainer may comprise a flow restrictor configured to be positionedaround the tooth chamber and within the cap. The cap may alsosubstantially seal the tooth chamber so as to allow for controlledingress and egress of fluid. The fluid retainer may be configured tomaintain the fluid pressure within the tooth at pressures below apredetermined pressure level. In addition, the pressure wave generatormay comprise one or more devices selected from the group consisting of:a fluid jet, a laser, a mechanical stirrer, and an ultrasonic device.Further, the pressure wave generator may be configured to produceacoustic energy waves capable of creating at least some fluid cavitationin the tooth chamber.

16. Examples of Apparatus with Pressure Wave Generators GeneratingFrequencies Above 1 kHz

In another aspect, an apparatus for treating a tooth is disclosed. Theapparatus comprises a body having a fluid chamber with an opening tocommunicate with a tooth chamber in a tooth when the body is disposedadjacent a tooth. The apparatus may further comprise a pressure wavegenerator having an energy outlet disposed within the fluid chamber. Thepressure wave generator may be configured to produce acoustic pressurewaves. At least a substantial amount of the produced acoustic pressurewaves can have frequencies of 1 kHz or greater.

In certain embodiments, the energy outlet can comprise a point or a setof points in the pressure wave generator that transmit energy into theambient medium (e.g., fluid in the tooth chamber). For example, theenergy outlet for some liquid jet devices may comprise a distal end of aguide tube having an impingement or reverberation surface. The jet mayimpact the impingement or reverberation surface and form a spray thatleaves the guide tube through one or more windows to interact with fluidin the tooth chamber. As another example, an energy outlet for anelectromagnetic laser device may comprise a tapered tip of an opticalfiber.

In other aspects, a substantial amount of the produced acoustic pressurewaves may have frequencies of 10 kHz or greater, or 100 kHz or greater.The acoustic pressure waves may have substantial power at frequenciesgreater than about 1 kHz, greater than about 10 kHz, greater than about100 kHz, or greater than about 500 kHz. Substantial power can include,for example, an amount of power that is greater than 10%, greater than25%, greater than 35%, or greater than 50% of the total acoustic power(e.g., the acoustic power integrated over all frequencies). The producedacoustic pressure waves may also have a bandwidth of at least about 10kHz, at least about 50 kHz, or at least about 100 kHz.

In some embodiments, the pressure wave generator may comprise one ormore devices selected from the group consisting of: a fluid jet, alaser, a mechanical stirrer, and an ultrasonic device. The pressure wavegenerator may also comprise a liquid jet. Additionally, the energyoutlet may comprise a reverberation surface, and the liquid jet may beconfigured to impact a portion of the reverberation surface. Theapparatus may further comprise a source of degassed liquid configured toprovide liquid for a liquid jet. In some cases, the body may beconfigured to substantially close an access opening into the toothchamber, and the body may further comprise a vent to regulate fluidpressure within the tooth chamber. The body can substantially close theaccess opening to retain most or substantially all of the fluid in thetooth chamber by providing a water-resistant seal between the retainerand the tooth. The body may, but need not, retain all the fluid in thetooth chamber. For example substantially retaining fluid in the toothchamber does not require that there be no amount of leakage of the fluidfrom the tooth chamber. The body can be applied to the tooth to reduceor minimize the amount of fluid that leaks into the patient's mouthduring treatment, which may improve patient safety and experience sincesome fluids can contain caustic or unpleasant tasting substances.

In yet other aspects, the body may comprise a fluid outlet port forremoval of fluid from the tooth chamber, and the body may furthercomprise a vent in fluid communication with the fluid outlet port. Insome cases, the vent may be configured to permit air to be entrainedinto flow of fluid removed from the tooth chamber via the fluid outletport, and the vent may further be configured to inhibit flow of air intothe tooth chamber.

17. Examples of Procedures for Treating a Tooth Using Vented Ports

In another aspect, a procedure for treating a tooth is disclosed. Theprocedure comprises forming at least an access opening into a toothchamber in a tooth, closing the tooth chamber using a fluid retainerapplied to the tooth, and introducing fluid through an ingress port intoat least a portion of the tooth chamber. The procedure may furthercomprise removing fluid from the tooth chamber through an egress port,and venting fluid from the tooth chamber through a vent port when fluidpressure within the tooth chamber generally exceeds a predefinedpressure level. Further, the procedure may comprise inhibiting air flowinto the tooth chamber through the vent port.

In some aspects, venting fluid from the tooth chamber may furthercomprise permitting at least some air flow to be entrained with fluidremoved from the tooth chamber. In some cases, introducing fluid maycomprise introducing a degassed liquid. The procedure may furthercomprise inserting a pressure wave generator into the tooth chamber andat least partially below a fluid level of the introduced fluid. Theprocedure may also comprise activating the pressure wave generator inthe tooth chamber to produce acoustic energy waves in the fluid. In somecases, the acoustic energy waves may retain sufficient energy to createat least some fluid cavitation within the tooth chamber. In someembodiments, the procedure may comprise using the fluid retainer toinhibit uncontrolled flow of fluid. Further, using the fluid retainer toinhibit uncontrolled flow may include retaining sufficient fluid withinthe tooth chamber to permit the acoustic energy waves to propagatewithin the fluid.

In some aspects, using the fluid retainer may involve positioning a caparound the tooth chamber such that the cap substantially closes theaccess opening into the tooth chamber. The procedure may also comprisepositioning the cap on a tooth seal region of the tooth. In some cases,the tooth seal region may comprise a tooth seal. In addition,positioning the cap on the tooth seal region may comprise planarizing asurface of the tooth seal. In some embodiments, using the fluid retainermay involve positioning a flow restrictor around the tooth chamber andwithin the cap. Additionally, positioning the cap on the tooth sealregion may substantially seal the tooth chamber so as to allow forcontrolled ingress and egress of fluid.

18. Examples of Apparatus for Treating a Tooth Using Vented Ports

In another embodiment, an apparatus for treating a tooth comprises afluid retainer configured to be applied to the tooth to substantiallyretain fluid in a tooth chamber in the tooth. A suction port on thefluid retainer may be configured to remove fluid from the tooth chamber.The apparatus may further comprise a vent in fluid communication withthe suction port. The vent may be configured to permit air to beentrained into the flow of fluid removed from the tooth chamber via thesuction port. In addition, the vent may further be configured to inhibitflow of air into the chamber in the tooth.

In some aspects, the apparatus may comprise an inlet port configured todeliver fluid into the tooth chamber. In some cases, the vent maycomprise an elongated shape with a ratio of length to width greater thanabout 1.5 to 1. The vent may also be configured such that pressure ofthe fluid at an apex of the tooth (or in the tooth chamber) is less thanabout 100 mmHg. In some embodiments, the vent may further be configuredto allow degassed fluid to exit the tooth chamber. The vent may comprisea plurality of vents. In some aspects, the apparatus may furthercomprise a housing in fluid connection with the suction port.

The apparatus may comprise a pressure wave generator having a distalportion. The distal portion of the pressure wave generator may beconfigured to be inserted through the fluid retainer into the toothchamber. In some cases, the pressure wave generator may comprise one ormore devices selected from the group consisting of: a fluid jet, alaser, a mechanical stirrer, and an ultrasonic device. The pressure wavegenerator may also be configured to generate acoustic energy waves. Insome embodiments, the fluid retainer may be configured to retainsufficient fluid within the tooth chamber to permit acoustic energywaves to propagate within the fluid. Additionally, a substantial amountof the acoustic energy waves generated by the pressure wave generatormay retain sufficient energy to create at least some fluid cavitationwithin the tooth chamber.

In some aspects, the fluid retainer may comprise a flow restrictor. Insome embodiments, the flow restrictor may comprise a sponge or a vent.The fluid retainer may also be configured to substantially inhibitleakage of fluid, organic material, or both from the tooth chamber. Insome aspects, the fluid retainer may comprise a cap. The cap may beconfigured to be positioned around the tooth chamber such that the capsubstantially closes an access opening into the tooth chamber. Further,the cap may be configured to be positioned on a tooth seal region of thetooth, and the cap may include a planar surface that mates to a toothseal having a planar surface. In some cases, the pressure wave generatormay be configured to create at least some fluid cavitation in the toothchamber. Also, in some embodiments, the fluid retainer may be in fluidconnection with a distal portion of a housing. In some aspects, thefluid retainer may comprise a flow restrictor configured to bepositioned around the tooth chamber and within the cap. The cap may alsosubstantially seal the tooth chamber so as to allow for controlledingress and egress of fluid.

19. Examples of Methods of Cleaning a Tooth Using Degassed Fluids

In another embodiment, a method of treating a tooth comprises forming atleast an access opening into a tooth chamber in a tooth, introducingdegassed liquid from a source of degassed liquid into the tooth chamber,and cleaning organic material from dentin in the tooth using thedegassed liquid.

In other embodiments, the method may further comprise providing thedegassed liquid from a reservoir of degassed liquid. The method may alsocomprise providing the degassed liquid from a degassing system. Thedegassed liquid may have an amount of dissolved gases less than 18 mg/L,less than 12 mg/L, less than 6 mg/L, or less than 3 mg/L. In someaspects, introducing the degassed liquid may comprise irrigating thetooth chamber with the degassed liquid. In yet other aspects,introducing the degassed liquid may comprise propagating a high velocityliquid beam into the tooth chamber, and the liquid beam may in somecases comprise the degassed liquid. In some embodiments, cleaning theorganic material may comprise generating pressure waves using the highvelocity liquid beam. Introducing the degassed liquid may also comprisecirculating the degassed liquid in the tooth chamber. The method mayfurther comprise cleaning inorganic material from dentin in the toothusing the degassed liquid. The degassed liquid may include a tissuedissolving agent. The degassed liquid may include a decalcifying agent.

20. Examples of Methods of Generating Acoustic Waves in Degassed Fluids

In another aspect, a method for treating a tooth comprises flowing adegassed fluid into a tooth chamber in a tooth, and generating acousticwaves in the degassed fluid in the tooth.

In some cases, flowing the degassed liquid may comprise propagating ahigh velocity liquid beam into the tooth chamber, and the liquid beammay further comprise the degassed liquid. Generating acoustic waves maycomprise generating acoustic waves using the high velocity liquid beam.In addition, flowing the degassed liquid may comprise circulating thedegassed liquid in the tooth chamber. The method may further comprisegenerating acoustic cavitation using the acoustic waves. The method maycomprise providing the degassed liquid from a reservoir of degassedliquid, and the method may further comprise providing the degassedliquid from a degassing system. In some cases, the degassed liquid mayhave an amount of dissolved gases less than 18 mg/L, less than 12 mg/L,less than 6 mg/L, or less than 3 mg/L. Further, the method may comprisecleaning organic or inorganic matter from the tooth chamber. Forexample, the acoustic waves may provide the cleaning, or the acousticwaves may induce cavitation effects that provide the cleaning.

21. Examples of Methods of Generating Liquid Beams Using Degassed Fluids

In another embodiment, a method of treating a tooth comprises providinga source of degassed liquid, and generating a collimated beam ofdegassed liquid from the source of degassed liquid. The method mayfurther comprise using the collimated beam of degassed liquid to producean acoustic wave within a tooth chamber in the tooth, and dissociatingorganic material within the tooth chamber using the acoustic wave.

In some aspects, generating the collimated beam of degassed liquid maycomprise passing the degassed liquid through an orifice. For example,the orifice may include an opening in a nozzle of a liquid jet devicewherein high-pressure liquid passes through the opening in the form of ahigh-velocity beam. In some cases, using the collimated beam of degassedliquid to produce the acoustic wave may comprise generating acousticpower at least having substantial power at frequencies greater thanabout 1 kHz, greater than about 10 kHz, or greater than about 100 kHz.Substantial power can include, for example, an amount of power that isgreater than 10%, greater than 25%, greater than 35%, or greater than50% of the total acoustic power (e.g., the acoustic power integratedover all frequencies). Further, using the collimated beam of degassedliquid to produce the acoustic wave may comprise generating acousticcavitation in the tooth chamber. The method may further comprisepropagating the acoustic wave through fluid in the tooth chamber. Insome cases, the degassed liquid may have an amount of dissolved gasesless than 18 mg/L, less than 12 mg/L, less than 6 mg/L, or less than 3mg/L.

22. Examples of Methods of Propagating Acoustic Pressure Waves inDegassed Fluids

In yet another embodiment, a method for treating a tooth comprisesintroducing a degassed liquid into a tooth chamber in a tooth, andproducing acoustic pressure waves in the degassed liquid. The method mayfurther comprise propagating the acoustic pressure waves through thedegassed liquid to surrounding dentin structure of the tooth. In somecases, the degassed liquid may have an amount of dissolved gases lessthan 18 mg/L, less than 12 mg/L, less than 6 mg/L, or less than 3 mg/L.

In some embodiments, introducing the degassed liquid may comprisepropagating a high velocity liquid beam into the tooth chamber. Theliquid beam may comprise the degassed liquid. Further, introducing thedegassed liquid may comprise circulating the degassed liquid in thetooth chamber. The method may further comprise cleaning organic orinorganic material from the dentin structure of the tooth. In somecases, the method may comprise generating acoustic cavitation using thepropagated acoustic pressure waves.

23. Examples of Methods of Inhibiting Gas Bubble Formation in DegassedFluids

In another aspect, a method for treating a tooth comprises introducing adegassed liquid into a tooth chamber in a tooth. The method may furthercomprise delivering energy into the degassed liquid to clean organic orinorganic material from the dentin of the tooth, whereby the degassedliquid inhibits formation of gas bubbles in the tooth chamber.

In some aspects, the degassed liquid may have a dissolved gas contentless than about 18 mg/L, less than about 12 mg/L, less than 6 mg/L, orless than 3 mg/L. In some cases, delivering energy may comprisedelivering electromagnetic energy. In yet other cases, delivering energymay comprise delivering acoustic energy. The energy may be deliveredusing a laser or a high-velocity liquid jet. Further, delivering energymay also comprise generating pressure waves using the delivered energy.

24. Examples of Methods of Penetrating Small Openings in a Tooth UsingDegassed Fluids

In another embodiment, a method for treating a tooth comprisesintroducing a degassed liquid into a tooth chamber in a tooth, andpromoting circulation of the degassed liquid within the tooth chamber.The degassed liquid may have a sufficiently low amount of dissolvedgasses so as to penetrate openings in the tooth chamber having adimension less than 500 microns.

In some embodiments, introducing the degassed liquid may compriseirrigating the tooth chamber with the degassed liquid. In other cases,introducing the degassed liquid may comprise propagating a high velocityliquid beam into the tooth chamber. The liquid beam may comprise thedegassed liquid. Promoting circulation may comprise substantiallyinhibiting flow of the degassed liquid out of the tooth chamber. In somecases, promoting circulation may comprise regulating a fluid pressure inthe tooth chamber. The amount of dissolved gasses may be less than 18mg/L, less than 12 mg/L, less than 6 mg/L, or less than 3 mg/L. Further,the amount of dissolved gasses may be sufficiently low so that thedegassed liquid can penetrate openings in the tooth chamber having adimension less than 250 microns, less than 100 microns, less than 50microns, less than 25 microns, less than 10 microns, less than 5microns, less than 3 microns, less than 2 microns, or less than 1 micronin various embodiments. The method may further comprise propagatingacoustic energy through the degassed fluid into the openings in thetooth chamber. In some cases, the method may further comprise cleaningthe openings in the tooth chamber using the acoustic energy.

25. Examples of Apparatus Comprising a Degassed Liquid Source

In yet other aspects, an apparatus for treating a tooth is disclosed.The apparatus comprises a degassed liquid source, and a fluid retainerconfigured to be applied to a tooth. The fluid retainer may include afluid inlet communicating with the degassed liquid source so as todeliver degassed fluid into a tooth chamber in the tooth.

In some aspects, the degassed liquid source may be configured to deliverdegassed fluid to clear organic material from the tooth. In some cases,the degassed fluid may be free of dissolved gases to less than 0.1% byvolume or less than 18 mg/L. In additional embodiments, the degassedfluid may have a percentage of dissolved oxygen less than about 7 mg/L.Further, the fluid retainer may be configured to substantially retaindegassed fluid in the tooth chamber. The fluid retainer may also beconfigured to substantially inhibit air flow into the tooth chamber. Insome aspects, the fluid retainer may include at least one fluid outlet.The fluid retainer may also be configured to substantially inhibitleakage of degassed fluid, organic material, or both from the toothchamber.

In some instances, the fluid retainer may comprise a cap. The cap may beconfigured to be positioned around the tooth chamber such that the capsubstantially closes an access opening into the tooth chamber. The capmay be configured to be positioned on a tooth seal region of the tooth.In some embodiments, the cap may include a planar surface that mates toa tooth seal having a planar surface. In some aspects, the apparatus mayalso comprise a pressure wave generator having an energy outlet disposedwithin the tooth chamber. The pressure wave generator may be configuredto create at least some fluid cavitation in the tooth chamber. In somecases, the fluid retainer may comprise a flow restrictor configured tobe positioned around the tooth chamber and within the cap. The cap mayalso substantially seal the tooth chamber so as to allow for controlledingress and egress of degassed fluid.

In addition, the fluid retainer may comprise one or more ventsconfigured to permit at least some of the degassed fluid to leave thetooth chamber while inhibiting air from entering the tooth chamber. Insome embodiments, the one or more vents may be configured to permit atleast some air flow to be entrained with degassed fluid leaving thetooth chamber. Further, the fluid retainer may comprise a fluid outletconfigured to permit fluid to flow from the tooth chamber.

In some embodiments, the apparatus may comprise a pressure wavegenerator having an energy outlet disposed within the tooth chamber. Thepressure wave generator may be configured to create at least some fluidcavitation in the tooth chamber. The apparatus may further comprise apressure wave generator having an energy outlet disposed within thetooth chamber. In some aspects, the fluid retainer may be configured tomaintain the fluid pressure within the tooth at pressures below apredetermined pressure level. In some instances, the pressure wavegenerator may comprise one or more devices selected from the groupconsisting of: a fluid jet, a laser, a mechanical stirrer, and anultrasonic device. The pressure wave generator may also be configured tocreate at least some fluid cavitation in the tooth chamber.

26. Examples of Apparatus Comprising a Fluid Introducer

In another aspect, an apparatus for treating a tooth comprises adegassed liquid source. The apparatus may further include a fluidintroducer configured to supply degassed fluid from the degassed liquidsource to a tooth chamber in a tooth. The fluid introducer may comprisea fluid inlet. The fluid inlet may have a distal end sized or shaped tofit in the tooth chamber.

In other aspects, the degassed liquid source may be configured todeliver degassed fluid to clear organic material from the tooth. In somecases, the degassed fluid may be free of dissolved gases to less than0.1% by volume or less than 18 mg/L. In other embodiments, the degassedfluid may have a percentage of dissolved oxygen less than about 7 mg/L.The fluid introducer may be configured to circulate the degassed fluidwithin the tooth chamber. In some cases, the degassed liquid source maycomprise a reservoir. A distal portion of the fluid introducer may beconfigured to be positioned within the tooth chamber.

In some embodiments, the fluid introducer may comprise a channelconfigured to permit the degassed fluid to flow therethrough. Thedegassed fluid may comprise a high-velocity fluid jet beam. The channelmay be configured to direct the fluid jet beam to impact an impingementmember positioned near a distal portion of the channel. The channel mayhave an opening at the distal portion of the channel, and the openingmay be configured to allow the fluid jet beam to exit the channel whenit impacts the impingement member. The apparatus may further comprise afluid retainer configured to substantially retain at least some of thefluid in the tooth chamber.

The fluid retainer may also be configured to substantially inhibit airflow into the tooth chamber. In some aspects, the fluid retainer maycomprise one or more vents configured to permit at least some of thedegassed fluid to leave the tooth chamber while inhibiting air fromentering the tooth chamber. In addition, the one or more vents may beconfigured to permit at least some air flow to be entrained withdegassed fluid leaving the tooth chamber. In some embodiments, the fluidretainer may further comprise a fluid outlet configured to permit fluidto flow from the tooth chamber.

In further embodiments, the apparatus may comprise a pressure wavegenerator having an energy outlet disposed within the tooth chamber. Thepressure wave generator may be configured to create at least some fluidcavitation in the tooth chamber. In some cases, the pressure wavegenerator may comprise one or more devices selected from the groupconsisting of: a fluid jet, a laser, a mechanical stirrer, and anultrasonic device.

27. Examples of Apparatus Comprising a Degassed Fluid and a PressureWave Generator

In another embodiment, an apparatus for treating a tooth comprises adegassed liquid source for providing degassed liquid, and a fluid inletconfigured to deliver degassed liquid from the degassed liquid sourceinto a tooth chamber in the tooth. The apparatus may further comprise apressure wave generator being configured to generate pressure waves inthe degassed liquid in the tooth chamber.

In some embodiments, the pressure wave generator may include an energyoutlet disposed within the tooth chamber. The pressure wave generatormay also be configured to create at least some fluid cavitation in thetooth chamber. In some cases, the pressure wave generator may compriseone or more devices selected from the group consisting of: a fluid jet,a laser, a mechanical stirrer, and an ultrasonic device. The degassedliquid may be free of dissolved gases to less than 0.1% by volume orless than 18 mg/L. In addition, the degassed liquid may have apercentage of dissolved oxygen less than about 7 mg/L. In some aspects,the apparatus may comprise a fluid retainer configured to substantiallyretain at least some of the degassed liquid in the tooth chamber. Thefluid retainer may also be configured to substantially inhibit air flowinto the tooth chamber.

28. Examples of Degassed Fluids Comprising a Tissue Dissolving Agent

In some aspects, a fluid for treating a tooth comprises a tissuedissolving agent. The fluid can have an amount of dissolved gas lessthan 18 mg/L. The fluid can have an amount of dissolved gas less than 12mg/L. The fluid can have an amount of dissolved gas less than 6 mg/L.The fluid can have an amount of dissolved gas less than 3 mg/L. Thefluid can have an amount of dissolved gas less than 1 mg/L. The gas cancomprise air (e.g., primarily nitrogen and oxygen). In some cases, thegas comprises oxygen, and the amount of dissolved oxygen is less than 7mg/L or less than 3 mg/L.

The tissue dissolving agent can have a concentration less than 6% byvolume, or less than 3% by volume, or less than 1% by volume. The tissuedissolving agent can comprise sodium hypochlorite. The fluid cancomprise water or saline. The saline can be isotonic, hypotonic, orhypertonic.

The fluid can further comprise nanoparticles, biologically-activeparticles, or a chemical agent comprising hydroxyl functional groups.The fluid can further comprise a decalcifying agent. The decalcifyingagent can comprise ethylenediaminetetraacetic acid (EDTA).

In other aspects, use of a fluid comprising a tissue dissolving agentwith the fluid having an amount of dissolved gas less than 18 mg/L fortreating a tooth is described. Treating a tooth can comprise at leastone of irrigating a tooth, cleaning a tooth, generating acoustic wavesin the fluid, producing a collimated beam of the fluid, propagatingacoustic waves through the fluid, inhibiting formation of gas bubbles inthe tooth chamber, or promoting circulation of the fluid in the toothchamber.

29. Examples of Degassed Fluids Comprising a Decalcifying Agent

In some aspects, a fluid for treating a tooth comprises a decalcifyingagent. The fluid can have an amount of dissolved gas less than 18 mg/L.The fluid can have an amount of dissolved gas less than 12 mg/L. Thefluid can have an amount of dissolved gas less than 6 mg/L. The fluidcan have an amount of dissolved gas less than 3 mg/L. The fluid can havean amount of dissolved gas less than 1 mg/L. The gas can comprise air(e.g., primarily nitrogen and oxygen). In some cases, the gas comprisesoxygen, and the amount of dissolved oxygen is less than 7 mg/L or lessthan 3 mg/L.

The decalcifying agent can have a concentration less than 6% by volume,or less than 3% by volume, or less than 1% by volume. The decalcifyingagent can comprise ethylenediaminetetraacetic acid (EDTA). The fluid cancomprise water or saline. The saline can be isotonic, hypotonic, orhypertonic.

The fluid can further comprise nanoparticles, biologically-activeparticles, or a chemical agent comprising hydroxyl functional groups.The fluid can further comprise a tissue dissolving agent. The tissuedissolving agent can comprise sodium hypochlorite (NaOCl).

In other aspects, use of a fluid comprising a decalcifying agent withthe fluid having an amount of dissolved gas less than 18 mg/L fortreating a tooth is described. Treating a tooth can comprise at leastone of irrigating a tooth, cleaning a tooth, generating acoustic wavesin the fluid, producing a collimated beam of the fluid, propagatingacoustic waves through the fluid, inhibiting formation of gas bubbles inthe tooth chamber, or promoting circulation of the fluid in the toothchamber.

30. Examples of Procedures for Maintaining Fluid in a Tooth Chamber

In another aspect, a procedure for maintaining fluid in a tooth chamberin a tooth comprises delivering a fluid into the tooth chamber in thetooth and permitting at least some of the fluid to leave the toothchamber while inhibiting air from entering the chamber.

In some aspects, delivering the fluid may comprise delivering a degassedfluid. Delivering the fluid may comprise positioning a fluid inletwithin the tooth chamber. In addition, positioning the fluid inlet maycomprise positioning a tube, and the fluid may flow through the tube. Insome embodiments, the procedure may also comprise activating a pressurewave generator that produces acoustic energy waves within the toothchamber. The procedure may further comprise providing a fluid retainerthat retains sufficient fluid within the tooth chamber such that theacoustic energy waves have sufficient energy to create at least somefluid cavitation within the tooth chamber. In some cases, activating thepressure wave generator may comprise activating a fluid jet beam.

In some aspects, permitting at least some of the fluid to leave thechamber may comprise providing one or more vents to regulate fluidpressure within the tooth chamber. Providing one or more vents maycomprise permitting at least some air flow to be entrained with fluidremoved from the tooth chamber. In some embodiments, the procedure maycomprise providing a fluid outlet configured to permit fluid to flowfrom the tooth chamber. Also, the procedure may comprise activating apressure wave generator that produces acoustic energy waves within thetooth chamber. In some aspects, the procedure may further compriseproviding a fluid retainer that retains sufficient fluid within thetooth chamber such that the acoustic energy waves have sufficient energyto create at least some fluid cavitation within the tooth chamber.

31. Examples of Apparatus for Maintaining Fluid in a Tooth Chamber

In another aspect, an apparatus for maintaining fluid in a tooth chamberin a tooth comprises a fluid retainer configured to be applied to thetooth to substantially retain fluid in the tooth chamber. The fluidretainer may include including one or more vents configured to permit atleast some of the fluid to leave the tooth chamber while inhibiting airfrom entering the tooth chamber. The apparatus may further comprise afluid inlet configured to deliver fluid into the tooth chamber.

In some aspects, a portion of the fluid inlet may further comprise apressure wave generator. The pressure wave generator may be configuredto produce acoustic energy waves. The acoustic energy waves may retainsufficient energy to create at least some fluid cavitation within thetooth chamber. In some embodiments, the fluid may comprise a degassedfluid. Additionally, the fluid inlet may comprise a channel configuredto permit the fluid to flow therethrough.

In some aspects, the apparatus may comprise a fluid outlet configured topermit the fluid to flow from the chamber. In some cases, the channelmay be configured to be positioned within the tooth chamber.Additionally, the fluid outlet may be configured to provide suction. Insome embodiments, the fluid may comprise a fluid jet beam. The fluidinlet may also comprise an impingement surface positioned near a distalportion of the channel. Further, the channel may be configured to directthe fluid jet beam to impact the impingement surface. In some aspects,the channel may be configured to direct the fluid jet beam such thatwhen the fluid jet beam impacts the impingement surface, an acousticenergy wave is produced. Also, the fluid retainer may be configured toretain sufficient fluid in the tooth chamber such that the acousticenergy waves can propagate with sufficient energy to cause at least somefluid cavitation within the tooth chamber.

32. Examples of Methods for Monitoring a Tooth

In another aspect, a method for monitoring fluid from a tooth comprisesdelivering a fluid to a tooth chamber in a tooth, removing fluid fromthe tooth chamber, and electronically monitoring a property of the fluidremoved from the tooth chamber. The fluid can be delivered or removedusing a fluid platform. The fluid can be delivered by a fluid inlet (orfluid introducer) or removed by a fluid outlet. A monitoring sensor(e.g., optical, electrical, or electrochemical) can be used to performthe electronic monitoring.

In other aspects, the method can further comprise activating ordeactivating a pressure wave generator based at least in part upon themonitored property. The method can further comprise activating ordeactivating a source that delivers the fluid into the tooth chamber.The activating or deactivating can be based at least in part upon themonitored property. Monitoring the property can comprise opticalmonitoring, and the property can comprise a reflectivity or atransmittivity of the fluid removed from the tooth chamber. Monitoringthe property can comprise electrical or electrochemical monitoring.

In other aspects, the method can further comprise communicatinginformation related to or derived from the monitored property to a userinterface. The user interface can include a display (e.g., an LCD), aweb browser, a mobile phone, a portable computer or tablet, etc.

The method can further comprise automatically adjusting a toothirrigation or cleaning device based at least in part on the monitoredproperty. The method can further comprise electronically monitoring aproperty of the fluid delivered to the tooth chamber. The method canfurther comprise automatically taking an action based at least in parton the monitored property of the fluid delivered to the tooth chamberand the monitored property of the fluid removed from the tooth chamber.The action can comprise one or more of: adjusting an endodonticapparatus, outputting information via a user interface, or providing analert.

33. Examples of Apparatus for Monitoring a Tooth

In another aspect, an apparatus for monitoring fluid from a toothcomprises a fluid inlet (or a fluid introducer) configured to deliverfluid to a tooth chamber in a tooth, a fluid outlet configured to removefluid from the tooth chamber, and a monitoring system configured tomonitor a property of the fluid removed from the tooth chamber. Forexample, the fluid inlet or fluid outlet may be in fluid communicationwith the tooth chamber via a fluid platform.

The monitoring system can comprise an optical sensor. The optical sensorcan be configured to measure a reflectivity or a transmittivity of thefluid removed from the tooth chamber. The monitoring system can comprisean electrical sensor or an electrochemical sensor.

The apparatus can further comprise an endodontic device, and theapparatus can be configured to adjust the endodontic device based atleast in part on the monitored property of the fluid removed from thetooth chamber. The endodontic device can comprise one or more devicesselected from the group consisting of: an irrigation device, a fluiddelivery device, a fluid removal device, a tooth cleaning device, and afluid platform. The tooth cleaning device can comprise a liquid jetdevice, a laser, an ultrasonic device, or a mechanical stirrer.

The monitoring system can be further configured to monitor a property ofthe fluid delivered to the tooth. The apparatus can further comprise aninterface system configured to output information related to or derivedfrom the monitored property. The apparatus can further comprise apressure wave generator, and the monitoring system can be configured toactivate or deactivate the pressure wave generator based at least inpart on the monitored property.

34. Examples of Apparatus for Cleaning a Tooth

In one aspect, an apparatus for cleaning a tooth comprises a fluidretainer configured to be applied to the tooth to substantially retainfluid in a tooth chamber of the tooth and a pressure wave generatorhaving a distal portion configured to be inserted into the toothchamber. The apparatus may also comprise a vent configured to regulatepressure in the tooth chamber.

In various embodiments, the fluid retainer can be configured to enablecirculation of the fluid within the tooth chamber. The fluid retainercan be configured to retain sufficient fluid in the tooth chamber suchthat the distal portion of the pressure wave generator remains submergedin the fluid. The fluid retainer can comprise a fluid inlet configuredto deliver fluid to the tooth chamber. The apparatus can furthercomprise a source of fluid. The source of fluid can be configured to bein fluid communication with the fluid inlet. The source of fluid cancomprise degassed fluid. The source of fluid can comprise a fluidcomprising a tissue dissolving agent or a decalcifying agent.

The fluid retainer can comprise a fluid outlet configured to removefluid from the tooth chamber. The vent can be in fluid communicationwith the fluid outlet. The vent can be configured to permit fluid fromthe tooth chamber to flow out of the vent when the pressure in the toothchamber exceeds a pressure threshold. The vent can be configured tosubstantially inhibit air from flowing into the tooth chamber. The ventcan be configured to allow ambient air to be entrained with fluid in thefluid outlet.

The apparatus can further comprise a monitoring sensor configured tomonitor a property of fluid in the fluid outlet. The apparatus can beconfigured to activate or deactivate the pressure wave sensor inresponse to a monitored property of the fluid in the fluid outlet. Themonitoring sensor can comprise an optical sensor, an electrical sensor,or an electrochemical sensor.

The pressure wave generator can comprises a liquid jet, a laser, anultrasonic device, a mechanical stirrer, or a combination thereof. Thepressure wave generator can be configured to generate an acoustic wavein the fluid retained in the tooth. The acoustic wave can have broadbandpower with a bandwidth greater than 10 kHz.

V. Conclusion

Although the tooth 10 schematically depicted in some of the figures is amolar, the procedures may be performed on any type of tooth such as anincisor, a canine, a bicuspid, a pre-molar, or a molar. Further,although the tooth may be depicted as a lower (mandibular) tooth in thefigures, this is for purposes of illustration, and is not limiting. Thesystems, methods, and compositions may be applied to lower (mandibular)teeth or upper (maxillary) teeth. Also, the disclosed apparatus andmethods are capable of treating root canal spaces having a wide range ofmorphologies, including highly curved root canal spaces. Moreover, thedisclosed apparatus, methods, and compositions may be applied to humanteeth (including juvenile teeth) and/or to animal teeth.

Reference throughout this specification to “some embodiments” or “anembodiment” means that a particular feature, structure, element, act, orcharacteristic described in connection with the embodiment is includedin at least one embodiment. Thus, appearances of the phrases “in someembodiments” or “in an embodiment” in various places throughout thisspecification are not necessarily all referring to the same embodimentand may refer to one or more of the same or different embodiments.Furthermore, the particular features, structures, elements, acts, orcharacteristics may be combined in any suitable manner (includingdifferently than shown or described) in other embodiments. Further, invarious embodiments, features, structures, elements, acts, orcharacteristics can be combined, merged, rearranged, reordered, or leftout altogether. Thus, no single feature, structure, element, act, orcharacteristic or group of features, structures, elements, acts, orcharacteristics is necessary or required for each embodiment. Allpossible combinations and subcombinations are intended to fall withinthe scope of this disclosure.

As used in this application, the terms “comprising,” “including,”“having,” and the like are synonymous and are used inclusively, in anopen-ended fashion, and do not exclude additional elements, features,acts, operations, and so forth. Also, the term “or” is used in itsinclusive sense (and not in its exclusive sense) so that when used, forexample, to connect a list of elements, the term “or” means one, some,or all of the elements in the list.

Similarly, it should be appreciated that in the above description ofembodiments, various features are sometimes grouped together in a singleembodiment, figure, or description thereof for the purpose ofstreamlining the disclosure and aiding in the understanding of one ormore of the various inventive aspects. This method of disclosure,however, is not to be interpreted as reflecting an intention that anyclaim require more features than are expressly recited in that claim.Rather, inventive aspects lie in a combination of fewer than allfeatures of any single foregoing disclosed embodiment.

The foregoing description sets forth various example embodiments andother illustrative, but non-limiting, embodiments of the inventionsdisclosed herein. The description provides details regardingcombinations, modes, and uses of the disclosed inventions. Othervariations, combinations, modifications, equivalents, modes, uses,implementations, and/or applications of the disclosed features andaspects of the embodiments are also within the scope of this disclosure,including those that become apparent to those of skill in the art uponreading this specification. Additionally, certain objects and advantagesof the inventions are described herein. It is to be understood that notnecessarily all such objects or advantages may be achieved in anyparticular embodiment. Thus, for example, those skilled in the art willrecognize that the inventions may be embodied or carried out in a mannerthat achieves or optimizes one advantage or group of advantages astaught herein without necessarily achieving other objects or advantagesas may be taught or suggested herein. Also, in any method or processdisclosed herein, the acts or operations making up the method or processmay be performed in any suitable sequence and are not necessarilylimited to any particular disclosed sequence.

What is claimed is:
 1. An apparatus for treating a root canal of atooth, the apparatus comprising: a fluid platform configured to bepositioned against the tooth so as to form a chamber bounded at least inpart by the fluid platform and a portion of the tooth; and a pressurewave generator having at least a distal portion configured to beinserted into the chamber and to be submerged in fluid in the chamber,the pressure wave generator producing acoustic pressure waves having abroadband power spectrum that includes significant power at frequenciesextending from 1 Hz to 100 kHz to clean the tooth, wherein the broadbandspectrum includes a first power at 1 kHz and a second power at 100 kHz,the first power being greater than the second power.
 2. The apparatus ofclaim 1, wherein the broadband power spectrum comprises power at leastat frequencies above about 100 kHz.
 3. The apparatus of claim 1, whereinthe broadband power spectrum has a bandwidth greater than about 250 kHz.4. The apparatus of claim 1, wherein the broadband power spectrum has abandwidth greater than about 500 kHz.
 5. The apparatus of claim 1,wherein the acoustic pressure waves have a broadband power spectrum witha bandwidth extending at least to 500 kHz.
 6. The apparatus of claim 1,wherein the fluid platform comprises an opening, and the pressure wavegenerator is configured to be inserted into the opening.
 7. Theapparatus of claim 1, wherein the pressure wave generator comprises oneor more devices selected from the group consisting of: a fluid jet, alaser, a mechanical stirrer, and an ultrasonic device.
 8. The apparatusof claim 1, wherein the distal portion of the pressure wave generatorcomprises an impingement surface, and the pressure wave generator isconfigured to form a liquid jet configured to impact the impingementsurface.
 9. The apparatus of claim 8, further comprising a source ofdegassed liquid configured to provide liquid for the liquid jet.
 10. Theapparatus of claim 1, wherein the fluid platform further comprising afluid retainer positioned around the pressure wave generator such thatthe fluid retainer substantially closes an access opening into thetooth.
 11. The apparatus of claim 1, wherein the fluid platform furthercomprising a fluid outlet port for removal of fluid from the chamber.12. The apparatus of claim 11, wherein the fluid platform furthercomprising a vent in fluid communication with the fluid outlet port. 13.The apparatus of claim 12, wherein the vent is configured to permit airto be entrained into flow of fluid removed from the tooth chamber viathe fluid outlet port, and the vent is further configured to inhibitflow of air into the tooth.
 14. The apparatus of claim 1, wherein thebroadband power spectrum has a bandwidth in a range from about 1 kHz toabout 500 MHz, the bandwidth being measurable in terms of a 3-decibelbandwidth criterion.
 15. The system of claim 1, wherein the bandwidth ofthe broadband power spectrum is measurable in terms of a 3-decibelbandwidth criterion.